NGG National Grid Plc New

Provision for bad and doubtful debts

£ 8,489

£ 9,444

(91)

(52)

Other operating costs

(6,425)

(7,697)

Other operating income

544

1,985

2,239

115

Share of post-tax results of joint ventures and associates

(800)

(661)

1,371

1,666

Tax

(307)

(447)

1,064

1,219

^[2]

Total profit for the period (continuing and discontinued)

^[2]

1,129

1,256

Attributable to:

Equity shareholders of the parent

1,128

1,256

Non-controlling interests

£ 1

£ 0

Earnings per share (pence)

Basic earnings per share (continuing) (in GBP per share)

£ 0.288

£ 0.334

Diluted earnings per share (continuing) (in GBP per share)

0.287

0.332

Basic earnings per share (continuing and discontinued) (in GBP per share)

0.306

0.344

Diluted earnings per share (continuing and discontinued) (in GBP per share)

£ 0.305

£ 0.342

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.
[2]	Comparative amounts have been re-presented to reflect the classification of the FAA option within the UK Gas Transmission business disposal group.

Consolidated statement of comprehensive income - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

^[1]

Statement of comprehensive income [abstract]

£ 1,064

£ 1,219

^[2]

Items from continuing operations that will never be reclassified to profit or loss:

^[2]

Remeasurement losses on pension assets and post-retirement benefit obligations

(263)

(631)

Net (losses)/gains in respect of cash flow hedging of capital expenditure

(2)

Tax on items that will never be reclassified to profit or loss

159

Total items from continuing operations that will never be reclassified to profit or loss

(201)

(458)

Items from continuing operations that may be reclassified subsequently to profit or loss:

Retranslation of net assets offset by net investment hedge

118

2,360

Exchange differences reclassified to the consolidated income statement on disposal

(145)

Net gains in respect of cash flow hedges

201

450

Net gains/(losses) in respect of cost of hedging

(64)

Net losses on investments in debt instruments measured at fair value through other comprehensive income

(16)

(47)

Share of other comprehensive income of associates, net of tax

Tax on items that may be reclassified subsequently to profit or loss

(59)

(86)

Total items from continuing operations that may be reclassified subsequently to profit or loss

284

2,469

Other comprehensive income for the period, net of tax, from continuing operations

2,011

Other comprehensive loss for the period, net of tax, from discontinued operations

(9)

(86)

Other comprehensive income for the period, net of tax

1,925

Total comprehensive income for the period from continuing operations

1,147

3,230

Total comprehensive income/(loss) for the period from discontinued operations

(49)

Equity shareholders of the parent from continuing operations

1,203

3,181

Attributable to:

1,146

3,227

Equity shareholders of the parent from discontinued operations

(49)

Equity shareholders of the parent

1,202

3,178

Non-controlling interests

£ 1

£ 3

[1]	Comparative amounts have been re-presented to reflect the classification of the FAA option within the UK Gas Transmission business disposal group.
[2]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Consolidated statement of changes in equity - GBP (£)
£ in Millions

Total

Total share-holders’ equity

Share capital

Share premium account

Retained earnings

Other equity reserves

Non-controlling interests

Equity, beginning balance at Mar. 31, 2022

£ 23,856

£ 23,833

£ 485

£ 1,300

£ 26,611

£ (4,563)

£ 23

Profit for the period

1,256

^[1]

1,256

Other comprehensive (loss)/income for the period

1,925

^[2]

1,922

(564)

2,486

Scrip dividend-related share issue

3,181

^[2]

3,178

692

2,486

Equity dividends

(1,119)

(1)

Issue of treasury shares

Transactions in own shares

(3)

Share-based payments

Cash flow hedges transferred to the statement of financial position, net of tax

Equity, ending balance at Sep. 30, 2022

25,957

25,931

486

1,304

26,215

(2,074)

Equity, beginning balance at Mar. 31, 2023

29,562

29,538

488

1,302

31,608

(3,860)

Profit for the period

1,129

1,128

Other comprehensive (loss)/income for the period

(199)

273

Scrip dividend-related share issue

1,203

1,202

929

273

Equity dividends

(1,325)

(1)

Issue of treasury shares

Transactions in own shares

(1)

Share-based payments

Cash flow hedges transferred to the statement of financial position, net of tax

Equity, ending balance at Sep. 30, 2023

£ 29,480

£ 29,455

£ 489

£ 1,301

£ 31,250

£ (3,585)

£ 25

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.
[2]	Comparative amounts have been re-presented to reflect the classification of the FAA option within the UK Gas Transmission business disposal group.

Consolidated statement of financial position - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023
Non-current assets
Goodwill	£ 9,905	£ 9,847
Other intangible assets	3,717	3,604
Property, plant and equipment	67,396	64,433
Other non-current assets	570	567
Pension assets	2,352	2,645
Financial and other investments	871	859
Investments in joint ventures and associates	1,414	1,300
Derivative financial assets	325	276
Total non-current assets	86,550	83,531
Current assets
Inventories and current intangible assets	931	876
Trade and other receivables	3,340	3,883
Current tax assets	18	43
Financial and other investments	1,680	2,605
Derivative financial assets	60	153
Cash and cash equivalents	227	163
Assets held for sale	1,441	1,443
Total current assets	7,697	9,166
Total assets	94,247	92,697
Current liabilities
Borrowings	(2,691)	(2,955)
Derivative financial liabilities	(321)	(222)
Trade and other payables	(4,465)	(5,068)
Contract liabilities	(159)	(252)
Current tax liabilities	(231)	(236)
Provisions	(361)	(288)
Liabilities held for sale	(51)	(109)
Total current liabilities	(8,279)	(9,130)
Non-current liabilities
Borrowings	(42,106)	(40,030)
Derivative financial liabilities	(1,116)	(1,071)
Other non-current liabilities	(1,004)	(921)
Contract liabilities	(1,904)	(1,754)
Deferred tax liabilities	(7,318)	(7,181)
Pensions and other post-retirement benefit obligations	(615)	(694)
Provisions	(2,425)	(2,354)
Total non-current liabilities	(56,488)	(54,005)
Total liabilities	(64,767)	(63,135)
Net assets	29,480	29,562
Equity
Share capital	489	488
Share premium account	1,301	1,302
Retained earnings	31,250	31,608
Other equity reserves	(3,585)	(3,860)
Total shareholders’ equity	29,455	29,538
Non-controlling interests	25	24
Total equity	£ 29,480	£ 29,562

Consolidated cash flow statement - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Cash flows from operating activities

Gain on sale of investments

£ 1,985

£ 2,239

^[1]

Adjustments for:

(511)

Other fair value movements

(19)

Depreciation, amortisation and impairment

1,021

932

Share-based payments

Changes in working capital

(10)

(378)

Changes in provisions

Changes in pensions and other post-retirement benefit obligations

(54)

Cash generated from operations – continuing operations

3,062

2,360

Tax paid

(201)

(88)

Net cash flow from operating activities – continuing operations

2,861

2,272

Net cash flow from operating activities – discontinued operations

256

Cash flows from investing activities

Purchases of intangible assets

(269)

(224)

Purchases of property, plant and equipment

(3,210)

(3,258)

Disposals of property, plant and equipment

Investments in joint ventures and associates

(151)

(376)

Dividends received from joint ventures and associates

121

107

Disposal of financial and other investments

Acquisition of financial investments

(32)

(62)

Net movements in short-term financial investments

885

599

Interest received

Cash inflows on derivatives

103

Cash outflows on derivatives

(4)

(377)

Insurance claim from loss of property, plant and equipment

Net cash flow used in investing activities – continuing operations

(2,410)

(445)

Net cash flow used in investing activities – discontinued operations

(181)

Cash flows from financing activities

Proceeds from issue of treasury shares

Transactions in own shares

(1)

Proceeds received from loans

3,033

9,047

Repayments of loans

(839)

(9,049)

Payments of lease liabilities

(61)

(78)

Net movements in short-term borrowings

(444)

380

Cash inflows on derivatives

201

Cash outflows on derivatives

(60)

(230)

Interest paid

(779)

(669)

Dividends paid to shareholders

(1,325)

(1,119)

Net cash flow used in financing activities – continuing operations

(388)

(1,501)

Net cash flow used in financing activities – discontinued operations

(334)

Net increase in cash and cash equivalents

Reclassification to held for sale

(5)

Exchange movements

Net cash and cash equivalents at start of period

163

182

Net cash and cash equivalents at end of period

227

259

The Narragansett Electric Company

Cash flows from investing activities

Disposal of interest in The Narragansett Electric Company

^[2]

2,968

National Grid Renewables and Emerald Energy Venture LLC

Cash flows from investing activities

Contributions to National Grid Renewables and Emerald Energy Venture LLC

£ (5)

£ (8)

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.
[2]	The balance for the period ended 30 September 2022 consists of cash proceeds received, net of cash disposed.

Basis of preparation and new accounting standards, interpretations and amendments	6 Months Ended
	Sep. 30, 2023
Accounting Policies, Changes In Accounting Estimates And Errors [Abstract]
Basis of preparation	1. Basis of preparation and new accounting standards, interpretations and amendments The half year financial information covers the six month periods ended 30 September 2023 and 30 September 2022 and has been prepared in accordance with IAS 34 ‘Interim Financial Reporting’ as issued by the International Accounting Standards Board (IASB). This condensed set of financial statements comprises the unaudited financial information for the half years ended 30 September 2023 and 2022, together with the audited consolidated statement of financial position as at 31 March 2023. The half year financial information has been prepared applying consistent accounting policies to those applied by the Group for the year ended 31 March 2023. The notes to the unaudited financial information are prepared on a continuing basis unless otherwise stated. The financial information for the six months ended 30 September 2023 does not constitute statutory accounts as defined in Section 434 of the Companies Act 2006. It should be read in conjunction with the statutory accounts for the year ended 31 March 2023, which were prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the IASB. The key sources of estimation uncertainty and areas of judgement for the period ended 30 September 2023 are aligned to those disclosed in the Annual Report and Accounts for year ended 31 March 2023, with the following amendments: •whilst the entirety of the UK Electricity System Operator (ESO) is expected to transfer out of the Group to become part of an independent system operator public body, the Independent System Operator and Planner (ISOP), we have concluded that the held for sale criteria were not met as at 30 September 2023 due to the ESO not being available for sale in its present condition given the formation of the ISOP at the half year remained subject to legislative approval. The Group has identified this as an additional area of judgement in the period. The ESO was subsequently classified as held for sale at the end of October 2023 (see note 17); and •the value attributable to GasT TopCo Limited in determining the fair value of the options over the Group’s 40% interests (see note 6) is no longer considered to represent a key source of estimation uncertainty. 1. Basis of preparation and new accounting standards, interpretations and amendments (continued) Going concern As part of the Directors’ consideration of the appropriateness of adopting the going concern basis of accounting in preparing the half year financial information, the Directors have considered the Group’s principal risks (discussed on page 60) alongside potential downside business cash flow scenarios impacting the Group’s operations. The Directors specifically considered both a base case and a reasonable worst-case scenario for business cash flows. The assessment is prepared on the conservative assumption that the Group has no access to the debt capital markets. The main additional cash flow impacts identified in the reasonable worst-case scenario are: •the timing of the sale of assets classified as held for sale; •adverse impacts of inflation and incremental spend on our capital expenditure programme; •adverse impact from timing across the Group (i.e. a net under-recovery of allowed revenues or reductions in over-collections) and slower collections of outstanding receivables; •higher operating and financing costs than expected; including non-delivery of planned efficiencies across the Group; and •the potential impact of further significant storm costs in the US. As part of their analysis, the Board also considered the following potential levers at their discretion to improve the position identified by the analysis if the debt capital markets are not accessible: •the payment of dividends to shareholders; •significant changes in the phasing of the Group’s capital expenditure programme, with elements of non-essential works and programmes delayed; and •a number of further reductions in operating expenditure across the Group. As at 30 September 2023, the Group had undrawn committed facilities available for general corporate purposes amounting to £8.0 billion. Based on these available liquidity resources and having considered the reasonable worst-case scenario, and the further levers at the Board’s discretion, the Group has not identified any material uncertainties relating to events or conditions that, individually or collectively, may cast significant doubt on its ability to continue as a going concern for the foreseeable future, a period not less than 12 months from the date of this report. In addition to the above, the ability to raise new and extend existing financing was separately included in the analysis, and the Directors noted the c.£3.0 billion of new long-term senior debt issued in the period from 1 April to 30 September 2023 as evidence of the Group’s ability to continue to have access to the debt capital markets if needed. Based on the above, the Directors have concluded the Group is well placed to manage its financing and other business risks satisfactorily, and have a reasonable expectation that the Group will have adequate resources to continue in operation for at least 12 months from the signing date of these consolidated interim financial statements. They therefore consider it appropriate to adopt the going concern basis of accounting in preparing the half year financial information. New IFRS accounting standards, interpretations and amendments adopted in the period There are no new standards, interpretations or amendments, issued by the IASB or by the IFRS Interpretations Committee (IFRIC), that are applicable for the period commencing on 1 April 2023 and have had a material impact on the Group’s results. New IFRS accounting standards, interpretations and amendments not yet adopted There are no new accounting standards and amendments to existing standards that have been issued, but are not yet effective that were not disclosed in our Annual Report and Accounts. The Group has not early adopted any standard, amendment or interpretation that has been issued but is not yet effective.
New accounting standards, interpretations and amendments	1. Basis of preparation and new accounting standards, interpretations and amendments The half year financial information covers the six month periods ended 30 September 2023 and 30 September 2022 and has been prepared in accordance with IAS 34 ‘Interim Financial Reporting’ as issued by the International Accounting Standards Board (IASB). This condensed set of financial statements comprises the unaudited financial information for the half years ended 30 September 2023 and 2022, together with the audited consolidated statement of financial position as at 31 March 2023. The half year financial information has been prepared applying consistent accounting policies to those applied by the Group for the year ended 31 March 2023. The notes to the unaudited financial information are prepared on a continuing basis unless otherwise stated. The financial information for the six months ended 30 September 2023 does not constitute statutory accounts as defined in Section 434 of the Companies Act 2006. It should be read in conjunction with the statutory accounts for the year ended 31 March 2023, which were prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the IASB. The key sources of estimation uncertainty and areas of judgement for the period ended 30 September 2023 are aligned to those disclosed in the Annual Report and Accounts for year ended 31 March 2023, with the following amendments: •whilst the entirety of the UK Electricity System Operator (ESO) is expected to transfer out of the Group to become part of an independent system operator public body, the Independent System Operator and Planner (ISOP), we have concluded that the held for sale criteria were not met as at 30 September 2023 due to the ESO not being available for sale in its present condition given the formation of the ISOP at the half year remained subject to legislative approval. The Group has identified this as an additional area of judgement in the period. The ESO was subsequently classified as held for sale at the end of October 2023 (see note 17); and •the value attributable to GasT TopCo Limited in determining the fair value of the options over the Group’s 40% interests (see note 6) is no longer considered to represent a key source of estimation uncertainty. 1. Basis of preparation and new accounting standards, interpretations and amendments (continued) Going concern As part of the Directors’ consideration of the appropriateness of adopting the going concern basis of accounting in preparing the half year financial information, the Directors have considered the Group’s principal risks (discussed on page 60) alongside potential downside business cash flow scenarios impacting the Group’s operations. The Directors specifically considered both a base case and a reasonable worst-case scenario for business cash flows. The assessment is prepared on the conservative assumption that the Group has no access to the debt capital markets. The main additional cash flow impacts identified in the reasonable worst-case scenario are: •the timing of the sale of assets classified as held for sale; •adverse impacts of inflation and incremental spend on our capital expenditure programme; •adverse impact from timing across the Group (i.e. a net under-recovery of allowed revenues or reductions in over-collections) and slower collections of outstanding receivables; •higher operating and financing costs than expected; including non-delivery of planned efficiencies across the Group; and •the potential impact of further significant storm costs in the US. As part of their analysis, the Board also considered the following potential levers at their discretion to improve the position identified by the analysis if the debt capital markets are not accessible: •the payment of dividends to shareholders; •significant changes in the phasing of the Group’s capital expenditure programme, with elements of non-essential works and programmes delayed; and •a number of further reductions in operating expenditure across the Group. As at 30 September 2023, the Group had undrawn committed facilities available for general corporate purposes amounting to £8.0 billion. Based on these available liquidity resources and having considered the reasonable worst-case scenario, and the further levers at the Board’s discretion, the Group has not identified any material uncertainties relating to events or conditions that, individually or collectively, may cast significant doubt on its ability to continue as a going concern for the foreseeable future, a period not less than 12 months from the date of this report. In addition to the above, the ability to raise new and extend existing financing was separately included in the analysis, and the Directors noted the c.£3.0 billion of new long-term senior debt issued in the period from 1 April to 30 September 2023 as evidence of the Group’s ability to continue to have access to the debt capital markets if needed. Based on the above, the Directors have concluded the Group is well placed to manage its financing and other business risks satisfactorily, and have a reasonable expectation that the Group will have adequate resources to continue in operation for at least 12 months from the signing date of these consolidated interim financial statements. They therefore consider it appropriate to adopt the going concern basis of accounting in preparing the half year financial information. New IFRS accounting standards, interpretations and amendments adopted in the period There are no new standards, interpretations or amendments, issued by the IASB or by the IFRS Interpretations Committee (IFRIC), that are applicable for the period commencing on 1 April 2023 and have had a material impact on the Group’s results. New IFRS accounting standards, interpretations and amendments not yet adopted There are no new accounting standards and amendments to existing standards that have been issued, but are not yet effective that were not disclosed in our Annual Report and Accounts. The Group has not early adopted any standard, amendment or interpretation that has been issued but is not yet effective.

Segmental analysis

6 Months Ended

Sep. 30, 2023

Disclosure of operating segments [abstract]

Segmental analysis

2. Segmental analysis


UK Electricity Transmission			The high-voltage electricity transmission networks in England and Wales. This includes our Accelerated Strategic Transmission Investment projects to connect more clean, low-carbon power to the transmission network in England and Wales.
UK Electricity Distribution			The electricity distribution networks of NGED in the East Midlands, West Midlands and South West of England and South Wales.
UK Electricity System Operator			The Great Britain system operator. The ESO has not met the criteria to be classified as held for sale as at 30 September 2023.
New England			Gas distribution networks, electricity distribution networks and high-voltage electricity transmission networks in New England.
New York			Gas distribution networks, electricity distribution networks and high-voltage electricity transmission networks in New York.
National Grid Ventures			Comprises all commercial operations in LNG at the Isle of Grain in the UK and Providence, Rhode Island in the US, our electricity generation business in the US, our electricity interconnectors in the UK and our investment in National Grid Renewables Development LLC, our renewables business in the US. NGV operates outside our regulated core business. Our US LNG operations were reclassified from the New England segment following an internal reorganisation in the period.

2. Segmental analysis (continued)

(a)Revenue


Six months ended 30 September	2023			2022²
	Total sales	Sales between segments1	Sales to third parties	Total sales	Sales between segments1	Sales to third parties
	£m	£m	£m	£m	£m	£m
Operating segments – continuing operations:
UK Electricity Transmission	1,356	(19)	1,337	969	(14)	955
UK Electricity Distribution	850	(2)	848	1,005	(8)	997
UK Electricity System Operator	1,734	(17)	1,717	2,060	(15)	2,045
New England	1,441	—	1,441	1,760	—	1,760
New York	2,365	—	2,365	2,758	—	2,758
National Grid Ventures	666	(27)	639	685	(9)	676
Other	142	—	142	253	—	253
Total revenue from continuing operations	8,554	(65)	8,489	9,490	(46)	9,444

Geographical areas:
UK			4,309			4,589
US			4,180			4,855
Total revenue from continuing operations			8,489			9,444

2.Comparative amounts have been re-presented to reflect NGV as a separate operating segment.

(b)Operating profit/(loss)


	Before exceptional items and remeasurements		Exceptional items and remeasurements (see note 4)		After exceptional items and remeasurements
Six months ended 30 September	2023	2022¹	2023	2022¹	2023	2022¹
	£m	£m	£m	£m	£m	£m
Operating segments – continuing operations:
UK Electricity Transmission	839	499	(1)	(6)	838	493
UK Electricity Distribution	476	531	(4)	(9)	472	522
UK Electricity System Operator	443	147	—	(1)	443	146
New England	(32)	193	(15)	527	(47)	720
New York	(30)	(18)	38	(8)	8	(26)
National Grid Ventures	219	259	91	49	310	308
Other	(13)	145	(26)	(69)	(39)	76
Total operating profit from continuing operations	1,902	1,756	83	483	1,985	2,239

Geographical areas:
UK	1,956	1,550	60	(32)	2,016	1,518
US	(54)	206	23	515	(31)	721
Total operating profit from continuing operations	1,902	1,756	83	483	1,985	2,239

1.Comparative amounts have been re-presented to reflect NGV as a separate operating segment.


	Before exceptional items and remeasurements		Exceptional items and remeasurements (see note 4)		After exceptional items and remeasurements
Six months ended 30 September	2023	2022¹	2023	2022¹	2023	2022¹
	£m	£m	£m	£m	£m	£m
Reconciliation to profit before tax:
Operating profit from continuing operations	1,902	1,756	83	483	1,985	2,239
Share of post-tax results of joint ventures and associates	59	70	12	(19)	71	51
Finance income	123	69	(8)	(32)	115	37
Finance costs	(834)	(801)	34	140	(800)	(661)
Total profit before tax from continuing operations	1,250	1,094	121	572	1,371	1,666

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

2. Segmental analysis (continued)

(c)Capital expenditure

Capital expenditure represents additions to property, plant and equipment and other intangible assets but excludes additional investments in and loans to joint ventures and associates.


	Net book value of property, plant and equipment and other intangible assets		Capital expenditure		Depreciation, amortisation and impairment
	30 September 2023	31 March 2023¹	30 September 2023	30 September 2022¹	30 September 2023	30 September 2022¹
	£m	£m	£m	£m	£m	£m
Operating segments:
UK Electricity Transmission	16,030	15,483	800	629	(250)	(235)
UK Electricity Distribution	13,940	13,462	608	584	(105)	(104)
UK Electricity System Operator	434	411	75	42	(52)	(40)
New England	13,781	13,033	789	801	(204)	(184)
New York	22,937	21,730	1,257	1,242	(321)	(292)
National Grid Ventures	3,956	3,880	175	410	(84)	(73)
Other	35	38	2	9	(5)	(4)
Total	71,113	68,037	3,706	3,717	(1,021)	(932)

Geographical areas:
UK	33,475	32,343	1,649	1,594	(464)	(432)
US	37,638	35,694	2,057	2,123	(557)	(500)
Total	71,113	68,037	3,706	3,717	(1,021)	(932)

By asset type:
Property, plant and equipment	67,396	64,433	3,449	3,490	(868)	(829)
Other intangible assets	3,717	3,604	257	227	(153)	(103)
Total	71,113	68,037	3,706	3,717	(1,021)	(932)

Revenue

6 Months Ended

Sep. 30, 2023

Revenue [abstract]

Exceptional Items And Remeasurements [Abstract]

3. Revenue


Revenue for the six months ended 30 September 2023	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures £m	Other £m	Total £m
Revenue under IFRS 15
Transmission	1,299	—	5	43	283	426	—	2,056
Distribution	—	810	—	1,329	2,047	—	—	4,186
System Operator	—	—	1,712	—	—	—	—	1,712
Other1	9	36	—	4	7	75	—	131
Total IFRS 15 revenue	1,308	846	1,717	1,376	2,337	501	—	8,085
Other revenue
Generation	—	—	—	—	—	181	—	181
Other2	29	2	—	65	28	(43)	142	223
Total other revenue	29	2	—	65	28	138	142	404
Total revenue from continuing operations	1,337	848	1,717	1,441	2,365	639	142	8,489


Geographic split of revenue for the six months ended 30 September 2023	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures £m	Other £m	Total £m
Revenue under IFRS 15
UK	1,308	846	1,717	—	—	430	—	4,301
US	—	—	—	1,376	2,337	71	—	3,784
Total IFRS 15 revenue	1,308	846	1,717	1,376	2,337	501	—	8,085
Other revenue
UK	29	2	—	—	—	(50)	27	8
US	—	—	—	65	28	188	115	396
Total other revenue	29	2	—	65	28	138	142	404
Total revenue from continuing operations	1,337	848	1,717	1,441	2,365	639	142	8,489

3. Revenue (continued)


Revenue for the six months ended 30 September 2022	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures¹ £m	Other¹ £m	Total £m
Revenue under IFRS 15
Transmission	931	—	77	53	117	306	—	1,484
Distribution	—	940	—	1,675	2,617	—	—	5,232
System Operator	—	—	1,968	—	—	—	—	1,968
Other2	16	43	—	4	6	69	—	138
Total IFRS 15 revenue	947	983	2,045	1,732	2,740	375	—	8,822
Other revenue
Generation	—	—	—	—	—	224	—	224
Other3	8	14	—	28	18	77	253	398
Total other revenue	8	14	—	28	18	301	253	622
Total revenue from continuing operations	955	997	2,045	1,760	2,758	676	253	9,444


Geographic split of revenue for the six months ended 30 September 2022	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures¹ £m	Other¹ £m	Total £m
Revenue under IFRS 15
UK	947	983	2,045	—	—	310	—	4,285
US	—	—	—	1,732	2,740	65	—	4,537
Total IFRS 15 revenue	947	983	2,045	1,732	2,740	375	—	8,822
Other revenue
UK	8	14	—	—	—	83	199	304
US	—	—	—	28	18	218	54	318
Total other revenue	8	14	—	28	18	301	253	622
Total revenue from continuing operations	955	997	2,045	1,760	2,758	676	253	9,444

1.Comparative amounts have been re-presented to reflect NGV as a separate operating segment.

Exceptional items and remeasurements

6 Months Ended

Sep. 30, 2023

Exceptional items and remeasurements

4. Exceptional items and remeasurements


Six months ended 30 September 2023	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations
Cost efficiency programme	(39)	—	(39)
Transaction, separation and integration costs¹	(11)	—	(11)
IFA1 fire insurance proceeds	92	—	92
Net gains on commodity contract derivatives	—	41	41
	42	41	83


Six months ended 30 September 2022²	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations
Net gain on disposal of NECO	511	—	511
Cost efficiency programme	(61)	—	(61)
Transaction, separation and integration costs1	(65)	—	(65)
IFA1 fire insurance proceeds	33	—	33
Net gains on commodity contract derivatives	—	65	65
	418	65	483

1.Transaction, separation and integration costs represent the aggregate of distinct activities undertaken by the Group in the periods presented.

2.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

4. Exceptional items and remeasurements (continued)

Details of remeasurements, tax exceptional items and the tax effect of exceptional items and remeasurements are also provided in this note.


Six months ended 30 September 2023	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations	42	41	83





Included within net finance costs (note 5)
Net gains on derivative financial instruments	—	34	34
Net losses on financial assets at fair value through profit and loss	—	(8)	(8)
	—	26	26
Included within share of post-tax results of joint ventures and associates
Net gains on financial instruments	—	12	12
	—	12	12

Total included within profit before tax from continuing operations	42	79	121
Tax on exceptional items and remeasurements	1	(21)	(20)
Total exceptional items and remeasurements after tax from continuing operations	43	58	101


Six months ended 30 September 2022¹	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations	418	65	483






Included within net finance costs (note 5)
Net gains on derivative financial instruments	—	140	140
Net losses on financial assets at fair value through profit and loss	—	(32)	(32)
	—	108	108
Included within share of post-tax results of joint ventures and associates
Net losses on financial instruments	—	(19)	(19)
	—	(19)	(19)

Total included within profit before tax from continuing operations	418	154	572
Tax on exceptional items and remeasurements	(221)	(49)	(270)
Total exceptional items and remeasurements after tax from continuing operations	197	105	302

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Finance income and costs

6 Months Ended

Sep. 30, 2023

Analysis of income and expense [abstract]

Finance income and costs

5. Finance income and costs


		2023	2022¹
Six months ended 30 September	Notes	£m	£m
Finance income
Interest income from financing activities		52	14
Net interest on pensions and other post-retirement benefit obligations		51	41
Net losses on financial assets at fair value through profit and loss		(8)	(32)
Other interest income		20	14
		115	37
Finance costs
Interest expense on financial instruments2		(903)	(878)
Unwinding of discount on provisions		(50)	(42)
Other interest		(8)	8
Net gains on derivative financial instruments3		34	140
Less: interest capitalised4		127	111
		(800)	(661)

Net finance costs		(685)	(624)

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

3.Includes a net foreign exchange gain on borrowing activities, offset by foreign exchange losses and gains on financing derivatives measured at fair value.

Assets held for sale and discontinued operations

6 Months Ended

Sep. 30, 2023

Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract]

Assets held for sale and discontinued operations

6. Assets held for sale and discontinued operations

The following assets and liabilities were classified as held for sale:


	30 September 2023			31 March 2023
	Total assets held for sale £m	Total liabilities held for sale £m	Net assets held for sale £m	Total assets held for sale £m	Total liabilities held for sale £m	Net assets held for sale £m
Investment in GasT TopCo Limited	1,441	—	1,441	1,443	—	1,443
FAA option	—	—	—	—	(109)	(109)
FAA forward	—	(7)	(7)	—	—	—
RAA option	—	(44)	(44)	—	—	—
Net assets held for sale	1,441	(51)	1,390	1,443	(109)	1,334

6. Assets held for sale and discontinued operations (continued)

The summary income statements for the periods ended 30 September 2023 and 2022 are as follows:



	2023	2022¹
	£m	£m
Discontinued operations
Revenue	—	805
Other operating costs	—	(459)
Operating profit	—	346
Finance income	9	9
Finance costs²	61	(261)
Profit/(loss) before tax	70	94
Tax	(5)	(57)
Profit/(loss) after tax from discontinued operations	65	37

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

2.Finance costs include the remeasurement of the FAA option, the FAA forward and the RAA option.

The summary statements of comprehensive income are as follows:


	2023	2022¹
	£m	£m
Profit after tax from discontinued operations	65	37
Other comprehensive (loss)/income from discontinued operations
Items from discontinued operations that will never be reclassified to profit or loss:
Remeasurement losses on pension assets and post-retirement benefit obligations	—	(126)
Tax on items that will never be reclassified to profit or loss	—	31
Total losses from discontinued operations that will never be reclassified to profit or loss	—	(95)
Items from discontinued operations that may be reclassified subsequently to profit or loss:
Net gains in respect of cash flow hedges	—	8
Net gains in respect of cost of hedging	—	4
Net losses on investments in debt instruments measured at fair value through other comprehensive income	(12)	—
Tax on items that may be reclassified subsequently to profit or loss	3	(3)
Total (losses)/gains from discontinued operations that may be reclassified subsequently to profit or loss	(9)	9
Other comprehensive loss for the period, net of tax, from discontinued operations	(9)	(86)
Total comprehensive income/(loss) for the period from discontinued operations	56	(49)

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Tax from continuing operations	6 Months Ended
Tax from continuing operations	Sep. 30, 2023
Income taxes paid (refund) [abstract]
Tax from continuing operations	7. Tax from continuing operations The tax charge from continuing operations for the six month period ended 30 September 2023 is £307 million (2022: £447 million). It is based on management’s estimate of the weighted average effective tax rate by jurisdiction expected for the full year. The effective tax rate is 22.4% (2022: 26.8%), which includes the impact of our share of post-tax results of joint ventures and associates. The effective tax rate for the year ended 31 March 2023 was 24.4% including the impact of our share of post-tax results of joint ventures and associates. The legislation implementing the Organisation for Economic Co-operation and Development’s (OECD) proposals for a global minimum corporation tax rate (‘Pillar 2’) was enacted into UK law on 11 July 2023. The legislation includes an income inclusion rule and a domestic minimum tax, which together are designed to ensure a minimum effective tax rate of 15% in each country in which the Group operates. Similar legislation is being enacted by other governments around the world. The legislation is effective for National Grid from 1 April 2024 and therefore the rules do not impact the Group’s consolidated financial statements for year ended 31 March 2024. We have applied the mandatory exception in the UK to recognising and disclosing information about the deferred tax assets and liabilities related to Pillar 2 income taxes in accordance with the amendments to IAS 12 published by the IASB on 23 May 2023. The Group’s work is ongoing to assess the potential impact in the financial statements for year ended 31 March 2025.

Earnings per share

6 Months Ended

Sep. 30, 2023

Earnings per share [abstract]

Earnings per share

8. Earnings per share

The earnings per share (EPS) calculations are based on profit after tax attributable to equity shareholders of the parent company which excludes non-controlling interests.

(a)Basic earnings per share


	Earnings	EPS	Earnings	EPS
Six months ended 30 September	2023	2023	2022¹	2022¹
	£m	pence	£m	pence


Profit after tax from continuing operations attributable to the parent	1,063	28.8	1,219	33.4


Profit after tax from discontinued operations attributable to the parent	65	1.8	37	1


Total profit after tax attributable to the parent	1,128	30.6	1,256	34.4

		2023		2022
		millions		millions
Weighted average number of shares – basic		3,682		3,651

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

(b)Diluted earnings per share


	Earnings	EPS	Earnings	EPS
Six months ended 30 September	2023	2023	2022¹	2022¹
	£m	pence	£m	pence


Profit after tax from continuing operations attributable to the parent	1,063	28.7	1,219	33.2


Profit after tax from discontinued operations attributable to the parent	65	1.8	37	1


Total profit after tax attributable to the parent	1,128	30.5	1,256	34.2

		2023		2022
		millions		millions
Weighted average number of shares – diluted		3,700		3,668

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Dividends

6 Months Ended

Sep. 30, 2023

Subclassifications of assets, liabilities and equities [abstract]

Dividends

9. Dividends


	Pence per share	Cash dividend paid £m	Scrip dividend £m
Ordinary dividends
Final dividend in respect of the year ended 31 March 2023	37.60	1,325	56
Interim dividend in respect of the year ended 31 March 2023	17.84	488	163
Final dividend in respect of the year ended 31 March 2022	33.76	1,119	114

The Directors are proposing an interim dividend of 19.40 pence per share to be paid in respect of the year ending 31 March 2024. This would absorb £716 million of shareholders’ equity.

Fair value measurement

6 Months Ended

Sep. 30, 2023

Fair Value Measurement [Abstract]

Fair value measurement

10. Fair value measurement

Assets and liabilities measured at fair value


	30 September 2023				31 March 2023
	Level 1 £m	Level 2 £m	Level 3 £m	Total £m	Level 1 £m	Level 2 £m	Level 3 £m	Total £m
Assets
Investments held at fair value through profit and loss	1,007	—	483	1,490	1,764	—	452	2,216
Investments held at fair value through other comprehensive income1	—	388	—	388	—	407	—	407
Financing derivatives	—	309	20	329	—	341	22	363
Commodity contract derivatives	—	54	2	56	—	62	4	66
	1,007	751	505	2,263	1,764	810	478	3,052
Liabilities
Financing derivatives	—	(1,219)	(95)	(1,314)	—	(997)	(122)	(1,119)
Commodity contract derivatives	—	(78)	(45)	(123)	—	(134)	(40)	(174)

Contingent consideration2	—	—	(10)	(10)	—	—	(19)	(19)
	—	(1,297)	(150)	(1,447)	—	(1,131)	(181)	(1,312)
Total	1,007	(546)	355	816	1,764	(321)	297	1,740

1.Investments held include instruments which meet the criteria of IFRS 9 or IAS 19.

2.Contingent consideration relates to the acquisition of National Grid Renewables Development LLC.

The estimated fair value of total borrowings, excluding lease liabilities, using market values at 30 September 2023 is £38,354 million (31 March 2023: £38,219 million).

Our level 1 financial investments and liabilities held at fair value are valued using quoted prices from liquid markets and primarily comprise investments in short-term money market funds.

10. Fair value measurement (continued)

The impacts on a post-tax basis of reasonably possible changes in significant assumptions used in valuing assets and liabilities classified within level 3 of the fair value hierarchy are as follows:


	Financing derivatives		Commodity contract derivatives		Other
Six months ended 30 September	2023	2022	2023	2022	2023	2022
	£m	£m	£m	£m	£m	£m
10% increase in commodity prices	—	—	15	35	—	—
10% decrease in commodity prices	—	—	(15)	(36)	—	—
+10% market area price change	—	—	12	7	—	—
-10% market area price change	—	—	(11)	(7)	—	—
+20 basis point increase in Limited Price Index (LPI) market curve	(38)	(51)	—	—	—	—
-20 basis point decrease in LPI market curve	38	51	—	—	—	—
+20 basis point increase between Retail Price Index (RPI) and Consumer Price Index (CPI)	36	17	—	—	—	—
-20 basis point decrease between RPI and CPI market curves	(33)	(16)	—	—	—	—
+50 basis points change in discount rate	—	—	—	—	(8)	(9)
-50 basis points change in discount rate	—	—	—	—	9	10
+10% change in venture capital price	—	—	—	—	30	—
-10% change in venture capital price	—	—	—	—	(30)	—

The changes in fair value of our level 3 financial assets and liabilities in the six months to 30 September are presented below:


	Financing derivatives		Commodity contract derivatives		Other1		Total
	2023	2022	2023	2022	2023	2022	2023	2022
	£m	£m	£m	£m	£m	£m	£m	£m
At 1 April	(100)	(187)	(36)	44	433	376	297	233
Net gains/(losses) through the consolidated income statement for the period2,3	25	76	(4)	44	26	30	47	150
Purchases	—	(133)	(10)	(56)	11	37	1	(152)
Settlements	—	—	7	(4)	3	(4)	10	(8)
At 30 September4	(75)	(244)	(43)	28	473	439	355	223

4.There were no reclassifications in or out of level 3 (2022: none).

Net debt

6 Months Ended

Sep. 30, 2023

Subclassifications of assets, liabilities and equities [abstract]

Net debt

11. Net debt

Net debt is comprised as follows:


	30 September 2023	31 March 2023
	£m	£m
Cash and cash equivalents	227	163
Current financial investments	1,680	2,605
Borrowings and bank overdrafts	(44,797)	(42,985)
Financing derivatives1	(985)	(756)
Net debt (net of related derivative financial instruments)	(43,875)	(40,973)

The following table splits out the total derivative balances on the face of the consolidated statement of financial position by category:


	30 September 2023			31 March 2023
	Assets £m	Liabilities £m	Total £m	Assets £m	Liabilities £m	Total £m
Financing derivatives	329	(1,314)	(985)	363	(1,119)	(756)
Commodity contract derivatives	56	(123)	(67)	66	(174)	(108)
Total derivative financial instruments	385	(1,437)	(1,052)	429	(1,293)	(864)

Pensions and other post-retirement benefit obligations

6 Months Ended

Sep. 30, 2023

Employee Benefits [Abstract]

Pensions and other post-retirement benefit obligations

12. Pensions and other post-retirement benefit obligations


	30 September 2023	31 March 2023
	£m	£m
Present value of funded obligations	(17,502)	(18,934)
Fair value of plan assets	19,570	21,246
	2,068	2,312
Present value of unfunded obligations	(264)	(292)
Other post-employment liabilities	(67)	(69)
Net defined benefit asset	1,737	1,951
Presented in consolidated statement of financial position:
Assets	2,352	2,645
Liabilities	(615)	(694)
	1,737	1,951


Key actuarial assumptions	30 September 2023		31 March 2023
Discount rate – UK past service	5.55	%	4.80	%
Discount rate – US	5.70	%	4.85	%
Rate of increase in RPI – UK past service	3.19	%	3.17	%

Commitments and contingencies	6 Months Ended
Commitments and contingencies	Sep. 30, 2023
Subclassifications of assets, liabilities and equities [abstract]
Commitments and contingencies	13. Commitments and contingencies At 30 September 2023, there were commitments for future energy purchase agreements of £13,824 million (31 March 2023: £19,194 million) and future capital expenditure contracted but not provided for in relation to the acquisition of property, plant and equipment of £3,218 million (31 March 2023: £2,936 million). We also have contingencies in the form of certain guarantees and letters of credit. These are described in further detail in note 30 to the Annual Report and Accounts for the year ended 31 March 2023. Litigation and claims Through the ordinary course of our operations, we are party to various litigation, claims and investigations. We do not expect the ultimate resolution of any proceedings to have a material adverse effect on our results of operations, cash flows or financial position.

Exchange rates

6 Months Ended

Sep. 30, 2023

Foreign exchange rates [abstract]

Exchange rates

14. Exchange rates

The consolidated results are affected by the exchange rates used to translate the results of our US operations and US dollar transactions. The US dollar to pound sterling exchange rates used were:


30 September	2023	2022	Year ended 31 March 2023
Closing rate applied at period end	1.22	1.12	1.23
Average rate applied for the period	1.25	1.21	1.22

Related party transactions	6 Months Ended
Related party transactions	Sep. 30, 2023
Related party transactions [abstract]
Related party transactions	15. Related party transactionsRelated party transactions in the six months ended 30 September 2023 were substantially the same in nature to those disclosed in note 31 of the Annual Report and Accounts for the year ended 31 March 2023. There were no other related party transactions in the period that have materially affected the financial position or performance of the Group.

Additional disclosures in respect of guaranteed securities

6 Months Ended

Sep. 30, 2023

Separate Financial Statements [Abstract]

Additional disclosures in respect of guaranteed securities

16. Additional disclosures in respect of guaranteed securities


			National Grid plc and Niagara Mohawk Power Corporation combined £m
Combined statement of financial position
Non-current loans to other subsidiaries			126
Non-current assets			12,033
Current loans to other subsidiaries			15,557
Current assets			1,526
Current loans from other subsidiaries			(6,893)
Current liabilities			(1,263)
Non-current loans from other subsidiaries			(2,080)
Non-current liabilities			(13,703)
Net assets¹			5,303
Equity			5,303

Combined income statement – continuing operations
Revenue			1,594
Operating costs			(1,330)
Operating profit			264
Other income from other subsidiaries			—
Other income and costs, including taxation			(51)
Profit after tax			213

1.Excluded from net assets above are investments in other consolidated subsidiaries with a carrying value of £14,480 million.

Post balance sheet events	6 Months Ended
Post balance sheet events	Sep. 30, 2023
Disclosure of non-adjusting events after reporting period [abstract]
Post balance sheet events	17. Post balance sheet events At the end of October 2023, legislation required to enable the separation of the ESO and formation of the ISOP was passed through Parliament. The ISOP is expected to be established as a Public Corporation in 2024, with responsibilities across both the electricity and gas systems. As a result, the Group took the judgement to classify the associated assets and liabilities of the ESO as held for sale in the consolidated statement of financial position at the end of October 2023 and the ESO will be measured at the lower of its carrying amount or fair value less costs to sell, which will take into consideration the current over-collection of allowed revenues.

Basis of preparation and new accounting standards, interpretations and amendments (Policies)	6 Months Ended
	Sep. 30, 2023
Accounting Policies, Changes In Accounting Estimates And Errors [Abstract]
Going concern	Going concern As part of the Directors’ consideration of the appropriateness of adopting the going concern basis of accounting in preparing the half year financial information, the Directors have considered the Group’s principal risks (discussed on page 60) alongside potential downside business cash flow scenarios impacting the Group’s operations. The Directors specifically considered both a base case and a reasonable worst-case scenario for business cash flows. The assessment is prepared on the conservative assumption that the Group has no access to the debt capital markets. The main additional cash flow impacts identified in the reasonable worst-case scenario are: •the timing of the sale of assets classified as held for sale; •adverse impacts of inflation and incremental spend on our capital expenditure programme; •adverse impact from timing across the Group (i.e. a net under-recovery of allowed revenues or reductions in over-collections) and slower collections of outstanding receivables; •higher operating and financing costs than expected; including non-delivery of planned efficiencies across the Group; and •the potential impact of further significant storm costs in the US. As part of their analysis, the Board also considered the following potential levers at their discretion to improve the position identified by the analysis if the debt capital markets are not accessible: •the payment of dividends to shareholders; •significant changes in the phasing of the Group’s capital expenditure programme, with elements of non-essential works and programmes delayed; and •a number of further reductions in operating expenditure across the Group. As at 30 September 2023, the Group had undrawn committed facilities available for general corporate purposes amounting to £8.0 billion. Based on these available liquidity resources and having considered the reasonable worst-case scenario, and the further levers at the Board’s discretion, the Group has not identified any material uncertainties relating to events or conditions that, individually or collectively, may cast significant doubt on its ability to continue as a going concern for the foreseeable future, a period not less than 12 months from the date of this report. In addition to the above, the ability to raise new and extend existing financing was separately included in the analysis, and the Directors noted the c.£3.0 billion of new long-term senior debt issued in the period from 1 April to 30 September 2023 as evidence of the Group’s ability to continue to have access to the debt capital markets if needed. Based on the above, the Directors have concluded the Group is well placed to manage its financing and other business risks satisfactorily, and have a reasonable expectation that the Group will have adequate resources to continue in operation for at least 12 months from the signing date of these consolidated interim financial statements. They therefore consider it appropriate to adopt the going concern basis of accounting in preparing the half year financial information.
New IFRS accounting standards, interpretations and amendments adopted in the period	New IFRS accounting standards, interpretations and amendments adopted in the periodThere are no new standards, interpretations or amendments, issued by the IASB or by the IFRS Interpretations Committee (IFRIC), that are applicable for the period commencing on 1 April 2023 and have had a material impact on the Group’s results.
New IFRS accounting standards, interpretations and amendments not yet adopted	New IFRS accounting standards, interpretations and amendments not yet adopted There are no new accounting standards and amendments to existing standards that have been issued, but are not yet effective that were not disclosed in our Annual Report and Accounts. The Group has not early adopted any standard, amendment or interpretation that has been issued but is not yet effective.
Segment analysis	Revenue and the results of the business are analysed by operating segment, based on the information the Board use internally for the purposes of evaluating the performance of each operating segment and determining resource allocation between them. The Board is National Grid’s chief operating decision maker (as defined by IFRS 8 ‘Operating Segments’) and assesses the profitability of a profit measure that excludes certain income and expenses. We call that measure ‘adjusted profit’. Adjusted profit excludes exceptional items and remeasurements (as defined in note 4) and is used by management to monitor financial performance as it is considered that it aids the comparability of our reported financial performance from year to year. As a matter of course, the Board also considers profitability by segment, excluding the effect of major storms and timing adjustments relating to revenue and certain pass-through costs. However, the measure of profit disclosed in this note is operating profit before exceptional items and remeasurements, as this is the measure that is most consistent with the IFRS results reported within these financial statements.
Revenue	Under IFRS 15 ‘Revenue from Contracts with Customers’, revenue is recorded as or when the Group satisfies a performance obligation by transferring a promised good or service to a customer. A good or service is transferred when the customer obtains control of that good or service. The transfer of control of our distribution or transmission services coincides with the use of our network, as electricity and gas pass through our network and reach our customers. The Group principally satisfies its performance obligations over time and the amount of revenue recorded corresponds to the amounts billed and accrued for volumes of gas and electricity delivered/transferred to/from our customers.
Exceptional items and remeasurements	To monitor our segmental financial performance, we use an adjusted consolidated profit measure that excludes certain income and expenses. We exclude items from adjusted profit because, if included, these items could distort understanding of our performance in the period and the comparability between periods. With respect to restructuring costs, these represent additional expenses incurred that are not related to normal business and day‑to-day activities. These can take place over multiple reporting periods given the scale of the Group, the nature and complexity of the transformation initiatives and due to the impact of strategic transactions. Remeasurements comprise unrealised gains or losses recorded in the consolidated income statement arising from changes in the fair value of certain financial assets and liabilities categorised as held at fair value through profit and loss (FVTPL). Once the fair value movements are realised (for example, when the derivative matures), the previously recognised fair value movements are then reversed through remeasurements and recognised within earnings before exceptional items and remeasurements. These assets and liabilities include commodity contracts and derivative financial instruments to the extent that hedge accounting is either not achieved or is not effective. We have also classified the unrealised gains or losses reported in profit and loss on certain additional assets treated as FVTPL within remeasurements. These relate to financial assets (which fail the ‘solely payments of principal and interest test’ under IFRS 9), the money market fund investments used by Group Treasury for cash management purposes and the net foreign exchange gains and losses on borrowing activities. These are offset by foreign exchange losses and gains on financing derivatives measured at fair value. In all cases, these fair values increase or decrease because of changes in foreign exchange, commodity or other financial indices over which we have no control.
Assets held for sale and discontinued operations	Assets and businesses are classified as held for sale when their carrying amounts are recovered through sale rather than through continuing use. They only meet the held for sale condition when the assets are ready for immediate sale in their present condition, management is committed to the sale and it is highly probable that the sale will complete within one year. Depreciation ceases on assets and businesses when they are classified as held for sale and the assets and businesses are impaired if their carrying value exceeds their fair value less expected costs to sell.The results and cash flows of assets or businesses classified as held for sale or sold during the year, that meet the criteria of being a major separate line of business or geographical area of operation, are shown separately from our continuing operations, and presented within discontinued operations in the income statement and cash flow statement.
Earnings per share	The earnings per share (EPS) calculations are based on profit after tax attributable to equity shareholders of the parent company which excludes non-controlling interests.
Guaranteed securities	Niagara Mohawk Power Corporation, a wholly owned subsidiary of the Group, has issued preferred shares that are listed on a US national securities exchange and are guaranteed by National Grid plc. This guarantor commits to honour any liabilities should the company issuing the debt have any financial difficulties. In order to provide debt holders with information on the financial stability of the company providing the guarantee, we are required to disclose individual financial information for this company. We have chosen to include this information in the half year financial information.

Segmental analysis (Tables)

6 Months Ended

Sep. 30, 2023

Disclosure of operating segments [abstract]

Schedule of information by operating segments

The following table describes the main activities for each reportable operating segment:


UK Electricity Transmission			The high-voltage electricity transmission networks in England and Wales. This includes our Accelerated Strategic Transmission Investment projects to connect more clean, low-carbon power to the transmission network in England and Wales.
UK Electricity Distribution			The electricity distribution networks of NGED in the East Midlands, West Midlands and South West of England and South Wales.
UK Electricity System Operator			The Great Britain system operator. The ESO has not met the criteria to be classified as held for sale as at 30 September 2023.
New England			Gas distribution networks, electricity distribution networks and high-voltage electricity transmission networks in New England.
New York			Gas distribution networks, electricity distribution networks and high-voltage electricity transmission networks in New York.
National Grid Ventures			Comprises all commercial operations in LNG at the Isle of Grain in the UK and Providence, Rhode Island in the US, our electricity generation business in the US, our electricity interconnectors in the UK and our investment in National Grid Renewables Development LLC, our renewables business in the US. NGV operates outside our regulated core business. Our US LNG operations were reclassified from the New England segment following an internal reorganisation in the period.

Revenue


Six months ended 30 September	2023			2022²
	Total sales	Sales between segments1	Sales to third parties	Total sales	Sales between segments1	Sales to third parties
	£m	£m	£m	£m	£m	£m
Operating segments – continuing operations:
UK Electricity Transmission	1,356	(19)	1,337	969	(14)	955
UK Electricity Distribution	850	(2)	848	1,005	(8)	997
UK Electricity System Operator	1,734	(17)	1,717	2,060	(15)	2,045
New England	1,441	—	1,441	1,760	—	1,760
New York	2,365	—	2,365	2,758	—	2,758
National Grid Ventures	666	(27)	639	685	(9)	676
Other	142	—	142	253	—	253
Total revenue from continuing operations	8,554	(65)	8,489	9,490	(46)	9,444

Geographical areas:
UK			4,309			4,589
US			4,180			4,855
Total revenue from continuing operations			8,489			9,444

2.Comparative amounts have been re-presented to reflect NGV as a separate operating segment.

Operating profit/(loss)


	Before exceptional items and remeasurements		Exceptional items and remeasurements (see note 4)		After exceptional items and remeasurements
Six months ended 30 September	2023	2022¹	2023	2022¹	2023	2022¹
	£m	£m	£m	£m	£m	£m
Operating segments – continuing operations:
UK Electricity Transmission	839	499	(1)	(6)	838	493
UK Electricity Distribution	476	531	(4)	(9)	472	522
UK Electricity System Operator	443	147	—	(1)	443	146
New England	(32)	193	(15)	527	(47)	720
New York	(30)	(18)	38	(8)	8	(26)
National Grid Ventures	219	259	91	49	310	308
Other	(13)	145	(26)	(69)	(39)	76
Total operating profit from continuing operations	1,902	1,756	83	483	1,985	2,239

Geographical areas:
UK	1,956	1,550	60	(32)	2,016	1,518
US	(54)	206	23	515	(31)	721
Total operating profit from continuing operations	1,902	1,756	83	483	1,985	2,239

1.Comparative amounts have been re-presented to reflect NGV as a separate operating segment.


	Before exceptional items and remeasurements		Exceptional items and remeasurements (see note 4)		After exceptional items and remeasurements
Six months ended 30 September	2023	2022¹	2023	2022¹	2023	2022¹
	£m	£m	£m	£m	£m	£m
Reconciliation to profit before tax:
Operating profit from continuing operations	1,902	1,756	83	483	1,985	2,239
Share of post-tax results of joint ventures and associates	59	70	12	(19)	71	51
Finance income	123	69	(8)	(32)	115	37
Finance costs	(834)	(801)	34	140	(800)	(661)
Total profit before tax from continuing operations	1,250	1,094	121	572	1,371	1,666

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Capital expenditure

Capital expenditure represents additions to property, plant and equipment and other intangible assets but excludes additional investments in and loans to joint ventures and associates.


	Net book value of property, plant and equipment and other intangible assets		Capital expenditure		Depreciation, amortisation and impairment
	30 September 2023	31 March 2023¹	30 September 2023	30 September 2022¹	30 September 2023	30 September 2022¹
	£m	£m	£m	£m	£m	£m
Operating segments:
UK Electricity Transmission	16,030	15,483	800	629	(250)	(235)
UK Electricity Distribution	13,940	13,462	608	584	(105)	(104)
UK Electricity System Operator	434	411	75	42	(52)	(40)
New England	13,781	13,033	789	801	(204)	(184)
New York	22,937	21,730	1,257	1,242	(321)	(292)
National Grid Ventures	3,956	3,880	175	410	(84)	(73)
Other	35	38	2	9	(5)	(4)
Total	71,113	68,037	3,706	3,717	(1,021)	(932)

Geographical areas:
UK	33,475	32,343	1,649	1,594	(464)	(432)
US	37,638	35,694	2,057	2,123	(557)	(500)
Total	71,113	68,037	3,706	3,717	(1,021)	(932)

By asset type:
Property, plant and equipment	67,396	64,433	3,449	3,490	(868)	(829)
Other intangible assets	3,717	3,604	257	227	(153)	(103)
Total	71,113	68,037	3,706	3,717	(1,021)	(932)

Revenue (Tables)

6 Months Ended

Sep. 30, 2023

Revenue [abstract]

Schedule of disaggregation of revenue from contracts with customers


Revenue for the six months ended 30 September 2023	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures £m	Other £m	Total £m
Revenue under IFRS 15
Transmission	1,299	—	5	43	283	426	—	2,056
Distribution	—	810	—	1,329	2,047	—	—	4,186
System Operator	—	—	1,712	—	—	—	—	1,712
Other1	9	36	—	4	7	75	—	131
Total IFRS 15 revenue	1,308	846	1,717	1,376	2,337	501	—	8,085
Other revenue
Generation	—	—	—	—	—	181	—	181
Other2	29	2	—	65	28	(43)	142	223
Total other revenue	29	2	—	65	28	138	142	404
Total revenue from continuing operations	1,337	848	1,717	1,441	2,365	639	142	8,489


Geographic split of revenue for the six months ended 30 September 2023	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures £m	Other £m	Total £m
Revenue under IFRS 15
UK	1,308	846	1,717	—	—	430	—	4,301
US	—	—	—	1,376	2,337	71	—	3,784
Total IFRS 15 revenue	1,308	846	1,717	1,376	2,337	501	—	8,085
Other revenue
UK	29	2	—	—	—	(50)	27	8
US	—	—	—	65	28	188	115	396
Total other revenue	29	2	—	65	28	138	142	404
Total revenue from continuing operations	1,337	848	1,717	1,441	2,365	639	142	8,489


Revenue for the six months ended 30 September 2022	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures¹ £m	Other¹ £m	Total £m
Revenue under IFRS 15
Transmission	931	—	77	53	117	306	—	1,484
Distribution	—	940	—	1,675	2,617	—	—	5,232
System Operator	—	—	1,968	—	—	—	—	1,968
Other2	16	43	—	4	6	69	—	138
Total IFRS 15 revenue	947	983	2,045	1,732	2,740	375	—	8,822
Other revenue
Generation	—	—	—	—	—	224	—	224
Other3	8	14	—	28	18	77	253	398
Total other revenue	8	14	—	28	18	301	253	622
Total revenue from continuing operations	955	997	2,045	1,760	2,758	676	253	9,444


Geographic split of revenue for the six months ended 30 September 2022	UK Electricity Transmission £m	UK Electricity Distribution £m	UK Electricity System Operator £m	New England £m	New York £m	National Grid Ventures¹ £m	Other¹ £m	Total £m
Revenue under IFRS 15
UK	947	983	2,045	—	—	310	—	4,285
US	—	—	—	1,732	2,740	65	—	4,537
Total IFRS 15 revenue	947	983	2,045	1,732	2,740	375	—	8,822
Other revenue
UK	8	14	—	—	—	83	199	304
US	—	—	—	28	18	218	54	318
Total other revenue	8	14	—	28	18	301	253	622
Total revenue from continuing operations	955	997	2,045	1,760	2,758	676	253	9,444

1.Comparative amounts have been re-presented to reflect NGV as a separate operating segment.

Exceptional items and remeasurements (Tables)

6 Months Ended

Sep. 30, 2023

Exceptional Items And Remeasurements [Abstract]

Schedule of exceptional items and remeasurements from continuing operations


Six months ended 30 September 2023	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations
Cost efficiency programme	(39)	—	(39)
Transaction, separation and integration costs¹	(11)	—	(11)
IFA1 fire insurance proceeds	92	—	92
Net gains on commodity contract derivatives	—	41	41
	42	41	83


Six months ended 30 September 2022²	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations
Net gain on disposal of NECO	511	—	511
Cost efficiency programme	(61)	—	(61)
Transaction, separation and integration costs1	(65)	—	(65)
IFA1 fire insurance proceeds	33	—	33
Net gains on commodity contract derivatives	—	65	65
	418	65	483

1.Transaction, separation and integration costs represent the aggregate of distinct activities undertaken by the Group in the periods presented.

2.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Details of remeasurements, tax exceptional items and the tax effect of exceptional items and remeasurements are also provided in this note.


Six months ended 30 September 2023	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations	42	41	83





Included within net finance costs (note 5)
Net gains on derivative financial instruments	—	34	34
Net losses on financial assets at fair value through profit and loss	—	(8)	(8)
	—	26	26
Included within share of post-tax results of joint ventures and associates
Net gains on financial instruments	—	12	12
	—	12	12

Total included within profit before tax from continuing operations	42	79	121
Tax on exceptional items and remeasurements	1	(21)	(20)
Total exceptional items and remeasurements after tax from continuing operations	43	58	101


Six months ended 30 September 2022¹	Exceptional items £m	Remeasurements £m	Total £m
Included within operating profit from continuing operations	418	65	483






Included within net finance costs (note 5)
Net gains on derivative financial instruments	—	140	140
Net losses on financial assets at fair value through profit and loss	—	(32)	(32)
	—	108	108
Included within share of post-tax results of joint ventures and associates
Net losses on financial instruments	—	(19)	(19)
	—	(19)	(19)

Total included within profit before tax from continuing operations	418	154	572
Tax on exceptional items and remeasurements	(221)	(49)	(270)
Total exceptional items and remeasurements after tax from continuing operations	197	105	302

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Finance income and costs (Tables)

6 Months Ended

Sep. 30, 2023

Analysis of income and expense [abstract]

Schedule of finance income and costs


		2023	2022¹
Six months ended 30 September	Notes	£m	£m
Finance income
Interest income from financing activities		52	14
Net interest on pensions and other post-retirement benefit obligations		51	41
Net losses on financial assets at fair value through profit and loss		(8)	(32)
Other interest income		20	14
		115	37
Finance costs
Interest expense on financial instruments2		(903)	(878)
Unwinding of discount on provisions		(50)	(42)
Other interest		(8)	8
Net gains on derivative financial instruments3		34	140
Less: interest capitalised4		127	111
		(800)	(661)

Net finance costs		(685)	(624)

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

3.Includes a net foreign exchange gain on borrowing activities, offset by foreign exchange losses and gains on financing derivatives measured at fair value.

Assets held for sale and discontinued operations (Tables)

6 Months Ended

Sep. 30, 2023

Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract]

Schedule of assets and liabilities classified as held for sale

The following assets and liabilities were classified as held for sale:


	30 September 2023			31 March 2023
	Total assets held for sale £m	Total liabilities held for sale £m	Net assets held for sale £m	Total assets held for sale £m	Total liabilities held for sale £m	Net assets held for sale £m
Investment in GasT TopCo Limited	1,441	—	1,441	1,443	—	1,443
FAA option	—	—	—	—	(109)	(109)
FAA forward	—	(7)	(7)	—	—	—
RAA option	—	(44)	(44)	—	—	—
Net assets held for sale	1,441	(51)	1,390	1,443	(109)	1,334

Summary of discontinued operations

The summary income statements for the periods ended 30 September 2023 and 2022 are as follows:



	2023	2022¹
	£m	£m
Discontinued operations
Revenue	—	805
Other operating costs	—	(459)
Operating profit	—	346
Finance income	9	9
Finance costs²	61	(261)
Profit/(loss) before tax	70	94
Tax	(5)	(57)
Profit/(loss) after tax from discontinued operations	65	37

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

2.Finance costs include the remeasurement of the FAA option, the FAA forward and the RAA option.

The summary statements of comprehensive income are as follows:


	2023	2022¹
	£m	£m
Profit after tax from discontinued operations	65	37
Other comprehensive (loss)/income from discontinued operations
Items from discontinued operations that will never be reclassified to profit or loss:
Remeasurement losses on pension assets and post-retirement benefit obligations	—	(126)
Tax on items that will never be reclassified to profit or loss	—	31
Total losses from discontinued operations that will never be reclassified to profit or loss	—	(95)
Items from discontinued operations that may be reclassified subsequently to profit or loss:
Net gains in respect of cash flow hedges	—	8
Net gains in respect of cost of hedging	—	4
Net losses on investments in debt instruments measured at fair value through other comprehensive income	(12)	—
Tax on items that may be reclassified subsequently to profit or loss	3	(3)
Total (losses)/gains from discontinued operations that may be reclassified subsequently to profit or loss	(9)	9
Other comprehensive loss for the period, net of tax, from discontinued operations	(9)	(86)
Total comprehensive income/(loss) for the period from discontinued operations	56	(49)

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Earnings per share (Tables)

6 Months Ended

Sep. 30, 2023

Earnings per share [abstract]

Schedule of basic and diluted earnings per share

Basic earnings per share


	Earnings	EPS	Earnings	EPS
Six months ended 30 September	2023	2023	2022¹	2022¹
	£m	pence	£m	pence


Profit after tax from continuing operations attributable to the parent	1,063	28.8	1,219	33.4


Profit after tax from discontinued operations attributable to the parent	65	1.8	37	1


Total profit after tax attributable to the parent	1,128	30.6	1,256	34.4

		2023		2022
		millions		millions
Weighted average number of shares – basic		3,682		3,651

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

(b)Diluted earnings per share


	Earnings	EPS	Earnings	EPS
Six months ended 30 September	2023	2023	2022¹	2022¹
	£m	pence	£m	pence


Profit after tax from continuing operations attributable to the parent	1,063	28.7	1,219	33.2


Profit after tax from discontinued operations attributable to the parent	65	1.8	37	1


Total profit after tax attributable to the parent	1,128	30.5	1,256	34.2

		2023		2022
		millions		millions
Weighted average number of shares – diluted		3,700		3,668

1.Comparative amounts have been re-presented to reflect the classification of the FAA option as held for sale and within discontinued operations.

Dividends (Tables)

6 Months Ended

Sep. 30, 2023

Subclassifications of assets, liabilities and equities [abstract]

Schedule of dividends


	Pence per share	Cash dividend paid £m	Scrip dividend £m
Ordinary dividends
Final dividend in respect of the year ended 31 March 2023	37.60	1,325	56
Interim dividend in respect of the year ended 31 March 2023	17.84	488	163
Final dividend in respect of the year ended 31 March 2022	33.76	1,119	114

Fair value measurement (Tables)

6 Months Ended

Sep. 30, 2023

Fair Value Measurement [Abstract]

Schedule of fair value measurement of assets

The following table categorises these assets and liabilities by the valuation methodology applied in determining their fair value using the fair value hierarchy described on page 197 of the Annual Report and Accounts for the year ended 31 March 2023.


	30 September 2023				31 March 2023
	Level 1 £m	Level 2 £m	Level 3 £m	Total £m	Level 1 £m	Level 2 £m	Level 3 £m	Total £m
Assets
Investments held at fair value through profit and loss	1,007	—	483	1,490	1,764	—	452	2,216
Investments held at fair value through other comprehensive income1	—	388	—	388	—	407	—	407
Financing derivatives	—	309	20	329	—	341	22	363
Commodity contract derivatives	—	54	2	56	—	62	4	66
	1,007	751	505	2,263	1,764	810	478	3,052
Liabilities
Financing derivatives	—	(1,219)	(95)	(1,314)	—	(997)	(122)	(1,119)
Commodity contract derivatives	—	(78)	(45)	(123)	—	(134)	(40)	(174)

Contingent consideration2	—	—	(10)	(10)	—	—	(19)	(19)
	—	(1,297)	(150)	(1,447)	—	(1,131)	(181)	(1,312)
Total	1,007	(546)	355	816	1,764	(321)	297	1,740

1.Investments held include instruments which meet the criteria of IFRS 9 or IAS 19.

2.Contingent consideration relates to the acquisition of National Grid Renewables Development LLC.

The changes in fair value of our level 3 financial assets and liabilities in the six months to 30 September are presented below:


	Financing derivatives		Commodity contract derivatives		Other1		Total
	2023	2022	2023	2022	2023	2022	2023	2022
	£m	£m	£m	£m	£m	£m	£m	£m
At 1 April	(100)	(187)	(36)	44	433	376	297	233
Net gains/(losses) through the consolidated income statement for the period2,3	25	76	(4)	44	26	30	47	150
Purchases	—	(133)	(10)	(56)	11	37	1	(152)
Settlements	—	—	7	(4)	3	(4)	10	(8)
At 30 September4	(75)	(244)	(43)	28	473	439	355	223

4.There were no reclassifications in or out of level 3 (2022: none).

Schedule of fair value measurement of liabilities


	30 September 2023				31 March 2023
	Level 1 £m	Level 2 £m	Level 3 £m	Total £m	Level 1 £m	Level 2 £m	Level 3 £m	Total £m
Assets
Investments held at fair value through profit and loss	1,007	—	483	1,490	1,764	—	452	2,216
Investments held at fair value through other comprehensive income1	—	388	—	388	—	407	—	407
Financing derivatives	—	309	20	329	—	341	22	363
Commodity contract derivatives	—	54	2	56	—	62	4	66
	1,007	751	505	2,263	1,764	810	478	3,052
Liabilities
Financing derivatives	—	(1,219)	(95)	(1,314)	—	(997)	(122)	(1,119)
Commodity contract derivatives	—	(78)	(45)	(123)	—	(134)	(40)	(174)

Contingent consideration2	—	—	(10)	(10)	—	—	(19)	(19)
	—	(1,297)	(150)	(1,447)	—	(1,131)	(181)	(1,312)
Total	1,007	(546)	355	816	1,764	(321)	297	1,740

1.Investments held include instruments which meet the criteria of IFRS 9 or IAS 19.

2.Contingent consideration relates to the acquisition of National Grid Renewables Development LLC.

The changes in fair value of our level 3 financial assets and liabilities in the six months to 30 September are presented below:


	Financing derivatives		Commodity contract derivatives		Other1		Total
	2023	2022	2023	2022	2023	2022	2023	2022
	£m	£m	£m	£m	£m	£m	£m	£m
At 1 April	(100)	(187)	(36)	44	433	376	297	233
Net gains/(losses) through the consolidated income statement for the period2,3	25	76	(4)	44	26	30	47	150
Purchases	—	(133)	(10)	(56)	11	37	1	(152)
Settlements	—	—	7	(4)	3	(4)	10	(8)
At 30 September4	(75)	(244)	(43)	28	473	439	355	223

4.There were no reclassifications in or out of level 3 (2022: none).

Schedule of impacts of reasonably possible changes in significant Level 3 assumptions

The impacts on a post-tax basis of reasonably possible changes in significant assumptions used in valuing assets and liabilities classified within level 3 of the fair value hierarchy are as follows:


	Financing derivatives		Commodity contract derivatives		Other
Six months ended 30 September	2023	2022	2023	2022	2023	2022
	£m	£m	£m	£m	£m	£m
10% increase in commodity prices	—	—	15	35	—	—
10% decrease in commodity prices	—	—	(15)	(36)	—	—
+10% market area price change	—	—	12	7	—	—
-10% market area price change	—	—	(11)	(7)	—	—
+20 basis point increase in Limited Price Index (LPI) market curve	(38)	(51)	—	—	—	—
-20 basis point decrease in LPI market curve	38	51	—	—	—	—
+20 basis point increase between Retail Price Index (RPI) and Consumer Price Index (CPI)	36	17	—	—	—	—
-20 basis point decrease between RPI and CPI market curves	(33)	(16)	—	—	—	—
+50 basis points change in discount rate	—	—	—	—	(8)	(9)
-50 basis points change in discount rate	—	—	—	—	9	10
+10% change in venture capital price	—	—	—	—	30	—
-10% change in venture capital price	—	—	—	—	(30)	—

Net debt (Tables)

6 Months Ended

Sep. 30, 2023

Subclassifications of assets, liabilities and equities [abstract]

Schedule of components of net debt

Net debt is comprised as follows:


	30 September 2023	31 March 2023
	£m	£m
Cash and cash equivalents	227	163
Current financial investments	1,680	2,605
Borrowings and bank overdrafts	(44,797)	(42,985)
Financing derivatives1	(985)	(756)
Net debt (net of related derivative financial instruments)	(43,875)	(40,973)

Schedule of balance sheet allocation of derivative balances

The following table splits out the total derivative balances on the face of the consolidated statement of financial position by category:


	30 September 2023			31 March 2023
	Assets £m	Liabilities £m	Total £m	Assets £m	Liabilities £m	Total £m
Financing derivatives	329	(1,314)	(985)	363	(1,119)	(756)
Commodity contract derivatives	56	(123)	(67)	66	(174)	(108)
Total derivative financial instruments	385	(1,437)	(1,052)	429	(1,293)	(864)

Pensions and other post-retirement benefit obligations (Tables)

6 Months Ended

Sep. 30, 2023

Employee Benefits [Abstract]

Schedule of defined benefit plan recognised in balance sheet


	30 September 2023	31 March 2023
	£m	£m
Present value of funded obligations	(17,502)	(18,934)
Fair value of plan assets	19,570	21,246
	2,068	2,312
Present value of unfunded obligations	(264)	(292)
Other post-employment liabilities	(67)	(69)
Net defined benefit asset	1,737	1,951
Presented in consolidated statement of financial position:
Assets	2,352	2,645
Liabilities	(615)	(694)
	1,737	1,951

Schedule of key actuarial assumptions


Key actuarial assumptions	30 September 2023		31 March 2023
Discount rate – UK past service	5.55	%	4.80	%
Discount rate – US	5.70	%	4.85	%
Rate of increase in RPI – UK past service	3.19	%	3.17	%

Exchange rates (Tables)

6 Months Ended

Sep. 30, 2023

Foreign exchange rates [abstract]

Schedule of average and closing foreign exchange rates

The US dollar to pound sterling exchange rates used were:


30 September	2023	2022	Year ended 31 March 2023
Closing rate applied at period end	1.22	1.12	1.23
Average rate applied for the period	1.25	1.21	1.22

Additional disclosures in respect of guaranteed securities (Tables)

6 Months Ended

Sep. 30, 2023

Seperate Financial Statements [Abstract]

Disclosure of Combined Statement of Financial Position


			National Grid plc and Niagara Mohawk Power Corporation combined £m
Combined statement of financial position
Non-current loans to other subsidiaries			126
Non-current assets			12,033
Current loans to other subsidiaries			15,557
Current assets			1,526
Current loans from other subsidiaries			(6,893)
Current liabilities			(1,263)
Non-current loans from other subsidiaries			(2,080)
Non-current liabilities			(13,703)
Net assets¹			5,303
Equity			5,303

Combined income statement – continuing operations
Revenue			1,594
Operating costs			(1,330)
Operating profit			264
Other income from other subsidiaries			—
Other income and costs, including taxation			(51)
Profit after tax			213

1.Excluded from net assets above are investments in other consolidated subsidiaries with a carrying value of £14,480 million.

Disclosure of Combined Income Statement


			National Grid plc and Niagara Mohawk Power Corporation combined £m
Combined statement of financial position
Non-current loans to other subsidiaries			126
Non-current assets			12,033
Current loans to other subsidiaries			15,557
Current assets			1,526
Current loans from other subsidiaries			(6,893)
Current liabilities			(1,263)
Non-current loans from other subsidiaries			(2,080)
Non-current liabilities			(13,703)
Net assets¹			5,303
Equity			5,303

Combined income statement – continuing operations
Revenue			1,594
Operating costs			(1,330)
Operating profit			264
Other income from other subsidiaries			—
Other income and costs, including taxation			(51)
Profit after tax			213

1.Excluded from net assets above are investments in other consolidated subsidiaries with a carrying value of £14,480 million.

Basis of preparation and new accounting standards, interpretations and amendments (Details) - GBP (£) £ in Billions	Jul. 19, 2023	Mar. 31, 2023	Jan. 31, 2023	Sep. 30, 2023
Disclosure of detailed information about borrowings [line items]
Undrawn borrowing facilities				£ 8.0
GasT TopCo Limited
Disclosure of detailed information about borrowings [line items]
Proportion of ownership interest in associate	20.00%	40.00%	40.00%
Fixed interest rate bonds
Disclosure of detailed information about borrowings [line items]
Notional amount				£ 3.0

Segmental analysis - Narrative (Details)	Sep. 30, 2023 segment
Disclosure of operating segments [abstract]
Number of reportable operating segments	6

Segmental analysis - Schedule of revenue by segment (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

£ 8,489

£ 9,444

^[1]

4,309

4,589

UK Electricity Transmission

4,180

4,855

UK Electricity Distribution

1,337

955

UK Electricity System Operator

848

997

1,717

2,045

New England

1,441

1,760

New York

2,365

2,758

National Grid Ventures

639

676

Other

142

253

Operating segments

Operating segments | UK Electricity Transmission

8,554

9,490

Operating segments | UK Electricity Distribution

1,356

969

Operating segments | UK Electricity System Operator

850

1,005

Operating segments | New England

1,734

2,060

Operating segments | New York

1,441

1,760

Operating segments | National Grid Ventures

2,365

2,758

Operating segments | Other

666

685

142

253

Sales between segments

Sales between segments | UK Electricity Transmission

(65)

(46)

Sales between segments | UK Electricity Distribution

(19)

(14)

Sales between segments | UK Electricity System Operator

(2)

(8)

Sales between segments | New England

(17)

(15)

Sales between segments | New York

Sales between segments | National Grid Ventures

Sales between segments | Other

(27)

(9)

£ 0

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Segmental analysis - Schedule of operating profit/(loss) by segment (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Share of post-tax results of joint ventures and associates

£ 1,985

£ 2,239

^[1]

^[1]

115

^[1]

(800)

(661)

^[1]

1,371

1,666

^[1]

2,016

1,518

Operating segments | UK Electricity Transmission

(31)

721

Operating segments | UK Electricity Distribution

838

493

Operating segments | UK Electricity System Operator

472

522

Operating segments | New England

443

146

Operating segments | New York

(47)

720

Operating segments | National Grid Ventures

(26)

Operating segments | Other

310

308

Before exceptional items and remeasurements

(39)

Share of post-tax results of joint ventures and associates

1,902

1,756

123

(834)

(801)

Before exceptional items and remeasurements | UK

1,250

1,094

Before exceptional items and remeasurements | US

1,956

1,550

Before exceptional items and remeasurements | Operating segments | UK Electricity Transmission

(54)

206

Before exceptional items and remeasurements | Operating segments | UK Electricity Distribution

839

499

Before exceptional items and remeasurements | Operating segments | UK Electricity System Operator

476

531

Before exceptional items and remeasurements | Operating segments | New England

443

147

Before exceptional items and remeasurements | Operating segments | New York

(32)

193

Before exceptional items and remeasurements | Operating segments | National Grid Ventures

(30)

(18)

Before exceptional items and remeasurements | Operating segments | Other

219

259

Exceptional items and remeasurements (see note 4)

(13)

145

Share of post-tax results of joint ventures and associates

483

(19)

(8)

(32)

140

Exceptional items and remeasurements (see note 4) | UK

121

572

Exceptional items and remeasurements (see note 4) | US

(32)

Exceptional items and remeasurements (see note 4) | Operating segments | UK Electricity Transmission

515

Exceptional items and remeasurements (see note 4) | Operating segments | UK Electricity Distribution

(1)

(6)

Exceptional items and remeasurements (see note 4) | Operating segments | UK Electricity System Operator

(4)

(9)

Exceptional items and remeasurements (see note 4) | Operating segments | New England

(1)

Exceptional items and remeasurements (see note 4) | Operating segments | New York

(15)

527

Exceptional items and remeasurements (see note 4) | Operating segments | National Grid Ventures

(8)

Exceptional items and remeasurements (see note 4) | Operating segments | Other

Revenue from Contracts with Customers [line items]

£ (26)

£ (69)

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Segmental analysis - Schedule of capital expenditure by segment (Details) - GBP (£) £ in Millions	6 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2023
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	£ 71,113		£ 68,037
Capital expenditure	3,706	£ 3,717
Depreciation, amortisation and impairment	(1,021)	(932)
Operating segments \| UK Electricity Transmission
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	16,030		15,483
Capital expenditure	800	629
Depreciation, amortisation and impairment	(250)	(235)
Operating segments \| UK Electricity Distribution
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	13,940		13,462
Capital expenditure	608	584
Depreciation, amortisation and impairment	(105)	(104)
Operating segments \| UK Electricity System Operator
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	434		411
Capital expenditure	75	42
Depreciation, amortisation and impairment	(52)	(40)
Operating segments \| New England
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	13,781		13,033
Capital expenditure	789	801
Depreciation, amortisation and impairment	(204)	(184)
Operating segments \| New York
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	22,937		21,730
Capital expenditure	1,257	1,242
Depreciation, amortisation and impairment	(321)	(292)
Operating segments \| National Grid Ventures
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	3,956		3,880
Capital expenditure	175	410
Depreciation, amortisation and impairment	(84)	(73)
Operating segments \| Other
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	35		38
Capital expenditure	2	9
Depreciation, amortisation and impairment	(5)	(4)
UK
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	33,475		32,343
Capital expenditure	1,649	1,594
Depreciation, amortisation and impairment	(464)	(432)
US
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	37,638		35,694
Capital expenditure	2,057	2,123
Depreciation, amortisation and impairment	(557)	(500)
Property, plant and equipment
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	67,396		64,433
Capital expenditure	3,449	3,490
Depreciation, amortisation and impairment	(868)	(829)
Other intangible assets
Disclosure of operating segments [line items]
Net book value of property, plant and equipment and other intangible assets	3,717		£ 3,604
Capital expenditure	257	227
Depreciation, amortisation and impairment	£ (153)	£ (103)

Revenue (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

£ 8,085

£ 8,822

404

622

Revenue from Contracts with Customers [line items]

8,489

9,444

^[1]

4,301

4,285

304

Revenue from Contracts with Customers [line items]

4,309

4,589

3,784

4,537

396

318

UK Electricity Transmission

4,180

4,855

Revenue from Contracts with Customers [line items]

1,308

947

UK Electricity Transmission | UK

1,337

955

Revenue from Contracts with Customers [line items]

1,308

947

UK Electricity Transmission | US

Revenue from Contracts with Customers [line items]

UK Electricity Distribution

Revenue from Contracts with Customers [line items]

846

983

UK Electricity Distribution | UK

848

997

Revenue from Contracts with Customers [line items]

846

983

UK Electricity Distribution | US

Revenue from Contracts with Customers [line items]

UK Electricity System Operator

Revenue from Contracts with Customers [line items]

1,717

2,045

UK Electricity System Operator | UK

1,717

2,045

Revenue from Contracts with Customers [line items]

1,717

2,045

UK Electricity System Operator | US

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

New England

1,376

1,732

Revenue from Contracts with Customers [line items]

1,441

1,760

New England | UK

Revenue from Contracts with Customers [line items]

New England | US

1,376

1,732

Revenue from Contracts with Customers [line items]

New York

2,337

2,740

Revenue from Contracts with Customers [line items]

2,365

2,758

New York | UK

Revenue from Contracts with Customers [line items]

New York | US

2,337

2,740

Revenue from Contracts with Customers [line items]

National Grid Ventures

501

375

138

301

National Grid Ventures | UK

639

676

Revenue from Contracts with Customers [line items]

430

310

National Grid Ventures | US

(50)

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

188

218

Other

142

253

Revenue from Contracts with Customers [line items]

142

253

Other | UK

Revenue from Contracts with Customers [line items]

199

Other | US

Revenue from Contracts with Customers [line items]

115

Transmission

Transmission | UK Electricity Transmission

2,056

1,484

Revenue from Contracts with Customers [line items]

Transmission | UK Electricity Distribution

1,299

931

Revenue from Contracts with Customers [line items]

Transmission | UK Electricity System Operator

Revenue from Contracts with Customers [line items]

Transmission | New England

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

Transmission | New York

Transmission | National Grid Ventures

283

117

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

426

306

Transmission | Other

Revenue from Contracts with Customers [line items]

Distribution

Distribution | UK Electricity Transmission

4,186

5,232

Revenue from Contracts with Customers [line items]

Distribution | UK Electricity Distribution

Revenue from Contracts with Customers [line items]

Distribution | UK Electricity System Operator

810

940

Revenue from Contracts with Customers [line items]

Distribution | New England

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

1,329

1,675

Distribution | New York

Distribution | National Grid Ventures

2,047

2,617

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

Distribution | Other

Revenue from Contracts with Customers [line items]

System Operator

System Operator | UK Electricity Transmission

1,712

1,968

Revenue from Contracts with Customers [line items]

System Operator | UK Electricity Distribution

Revenue from Contracts with Customers [line items]

System Operator | UK Electricity System Operator

Revenue from Contracts with Customers [line items]

System Operator | New England

1,712

1,968

Revenue from Contracts with Customers [line items]

System Operator | New York

Revenue from Contracts with Customers [line items]

System Operator | National Grid Ventures

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

System Operator | Other

Revenue from Contracts with Customers [line items]

Generation

Generation | UK Electricity Transmission

181

224

Revenue from Contracts with Customers [line items]

Generation | UK Electricity Distribution

Revenue from Contracts with Customers [line items]

Generation | UK Electricity System Operator

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

Generation | New England

Revenue from Contracts with Customers [line items]

Generation | New York

Generation | National Grid Ventures

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

181

224

Generation | Other

Revenue from Contracts with Customers [line items]

Other

131

138

Other | UK Electricity Transmission

223

398

Revenue from Contracts with Customers [line items]

Other | UK Electricity Distribution

Revenue from Contracts with Customers [line items]

Other | UK Electricity System Operator

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

Other | New England

Revenue from Contracts with Customers [line items]

Other | New York

Other | National Grid Ventures

Revenue from Contracts with Customers [line items]

Revenue from Contracts with Customers [line items]

(43)

Other | Other

Included within operating profit from continuing operations

£ 142

£ 253

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Exceptional items and remeasurements - Schedule of exceptional items and remeasurements from continuing operations (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

£ 1,985

£ 2,239

^[1]

Net losses on financial assets at fair value through profit and loss

140

(8)

(32)

Included within share of post-tax results of joint ventures and associates

(685)

(624)

Share of post-tax results of joint ventures and associates

^[1]

1,371

1,666

^[1]

Included within operating profit from continuing operations

1,064

1,219

^[1],[2]

Total

Net gain on disposal of NECO

511

Cost efficiency programme

(39)

(61)

Transaction, separation and integration costs

(11)

(65)

IFA1 fire insurance proceeds

Net gains on commodity contract derivatives

483

Net losses on financial assets at fair value through profit and loss

140

(8)

(32)

Included within share of post-tax results of joint ventures and associates

108

Net gains on financial instruments

(19)

Share of post-tax results of joint ventures and associates

(19)

Tax on exceptional items and remeasurements

121

572

(20)

(270)

Included within operating profit from continuing operations

101

302

Exceptional items

Net gain on disposal of NECO

511

Cost efficiency programme

(39)

(61)

Transaction, separation and integration costs

(11)

(65)

IFA1 fire insurance proceeds

Net gains on commodity contract derivatives

418

Net losses on financial assets at fair value through profit and loss

Included within share of post-tax results of joint ventures and associates

Net gains on financial instruments

Share of post-tax results of joint ventures and associates

Tax on exceptional items and remeasurements

418

(221)

Included within operating profit from continuing operations

197

Remeasurements

Net gain on disposal of NECO

Cost efficiency programme

Transaction, separation and integration costs

IFA1 fire insurance proceeds

Net gains on commodity contract derivatives

Net losses on financial assets at fair value through profit and loss

140

(8)

(32)

Included within share of post-tax results of joint ventures and associates

108

Net gains on financial instruments

(19)

Share of post-tax results of joint ventures and associates

(19)

Tax on exceptional items and remeasurements

154

(21)

(49)

Interest income from financing activities

£ 58

£ 105

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.
[2]	Comparative amounts have been re-presented to reflect the classification of the FAA option within the UK Gas Transmission business disposal group.

Exceptional items and remeasurements - Narrative (Details) £ in Millions, $ in Billions			1 Months Ended	6 Months Ended		23 Months Ended
	May 25, 2022 GBP (£)	May 25, 2022 USD ($)	Nov. 30, 2021 GBP (£)	Sep. 30, 2023 GBP (£)	Sep. 30, 2022 GBP (£)	Sep. 30, 2023 GBP (£)
Cost efficiency programme
Disclosure Of Exceptional Items [Line Items]
Cost efficiency programme, annual savings target			£ 400
Cost efficiency programme, period			3 years
Exceptional items
Disclosure Of Exceptional Items [Line Items]
Expense of restructuring activities				£ 39	£ 61
Transaction, separation and integration costs				11	65
Cash outflows relating to transaction, separation and integration costs				9	59
Income from insurance recovery				92	33
Cash inflows relating to insurance recovery				0	33
Gains on disposals of investments					511
Exceptional items \| Cost efficiency programme
Disclosure Of Exceptional Items [Line Items]
Expense of restructuring activities				39	61	£ 142
Cash outflows relating to restructuring activities				£ 28	£ 38
Exceptional items \| The Narragansett Electric Company
Disclosure Of Exceptional Items [Line Items]
Proportion of ownership interest disposed	100.00%	100.00%
Consideration received	£ 3,100	$ 3.9

Finance income and costs (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Finance income

£ 52

£ 14

Net interest on pensions and other post-retirement benefit obligations

Net losses on financial assets at fair value through profit and loss

(8)

(32)

Other interest income

Interest expense on financial instruments

115

^[1]

Finance costs

(903)

(878)

Unwinding of discount on provisions

(50)

(42)

Other interest

(8)

Less: interest capitalised

140

127

111

(800)

(661)

^[1]

Principal accretion on inflation-linked debt

(685)

(624)

149

240

Principal accretion on inflation-linked swaps

£ 18

£ (5)

Capitalisation rate of borrowing costs eligible for capitalisation

4.70%

4.30%

Tax relief on capitalised interest

£ 21

£ 13

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Assets held for sale and discontinued operations - Schedule of assets and liabilities classified as held for sale (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Assets held for sale	£ 1,441	£ 1,443
Liabilities held for sale	(51)	(109)
Assets and liabilities classified as held for sale
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Assets held for sale	1,441	1,443
Liabilities held for sale	(51)	(109)
Net assets held for sale	1,390	1,334
Assets and liabilities classified as held for sale \| FAA option
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Assets held for sale	0	0
Liabilities held for sale	0	(109)
Net assets held for sale	0	(109)
Assets and liabilities classified as held for sale \| FAA forward
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Assets held for sale	0	0
Liabilities held for sale	(7)	0
Net assets held for sale	(7)	0
Assets and liabilities classified as held for sale \| RAA option
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Assets held for sale	0	0
Liabilities held for sale	(44)	0
Net assets held for sale	(44)	0
Assets and liabilities classified as held for sale \| GasT TopCo Limited
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Assets held for sale	1,441	1,443
Liabilities held for sale	0	0
Net assets held for sale	£ 1,441	£ 1,443

Assets held for sale and discontinued operations - Narrative (Details) - GBP (£) £ in Billions	Jul. 19, 2023	Mar. 31, 2023	Jan. 31, 2023
GasT TopCo Limited
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Proportion of ownership interest disposed	20.00%
Proportion of ownership interest in associate	20.00%	40.00%	40.00%
GasT TopCo Limited \| Consortium
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Proportion of ownership interest in associate			60.00%
UK Gas Transmission
Disclosure Of Detailed Information About Assets Held For Sale [Line Items]
Proportion of ownership interest disposed			100.00%
Portion of consideration received			£ 4.0
Portion of consideration received consisting of shareholding in acquirer			40.00%

Assets held for sale and discontinued operations - Summary of discontinued operations in the Income Statement (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Disclosure of analysis of single amount of discontinued operations [line items]

£ 8,489

£ 9,444

^[1]

1,985

2,239

^[1]

115

^[1]

(800)

(661)

^[1]

Profit/(loss) after tax from discontinued operations

1,371

1,666

^[1]

^[1],[2]

Discontinued operations

Disclosure of analysis of single amount of discontinued operations [line items]

Profit/(loss) after tax from discontinued operations

805

Other operating costs

(459)

346

Discontinued operations | After exceptional items and remeasurements

Disclosure of analysis of single amount of discontinued operations [line items]

Disclosure of analysis of single amount of discontinued operations [line items]

£ 61

£ (261)

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.
[2]	Comparative amounts have been re-presented to reflect the classification of the FAA option within the UK Gas Transmission business disposal group.

Assets held for sale and discontinued operations - Summary of discontinued operations in the Statement of Comprehensive Income (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Items from discontinued operations that will never be reclassified to profit or loss:

£ 65

£ 37

^[1],[2]

Remeasurement losses on pension assets and post-retirement benefit obligations

(263)

(631)

^[1]

Tax on items that will never be reclassified to profit or loss

159

^[1]

Total items from continuing operations that will never be reclassified to profit or loss

(201)

(458)

^[1]

Items from discontinued operations that may be reclassified subsequently to profit or loss:

Net gains in respect of cash flow hedges

201

450

^[1]

Net gains in respect of cost of hedging

(64)

^[1]

Net losses on investments in debt instruments measured at fair value through other comprehensive income

(16)

(47)

^[1]

Tax on items that may be reclassified subsequently to profit or loss

(59)

(86)

^[1]

Total items from continuing operations that may be reclassified subsequently to profit or loss

284

2,469

^[1]

Other comprehensive income for the period, net of tax

1,925

^[1]

Disclosure of analysis of single amount of discontinued operations [line items]

1,203

3,181

^[1]

Discontinued operations

Items from discontinued operations that will never be reclassified to profit or loss:

Remeasurement losses on pension assets and post-retirement benefit obligations

(126)

Tax on items that will never be reclassified to profit or loss

Total items from continuing operations that will never be reclassified to profit or loss

(95)

Items from discontinued operations that may be reclassified subsequently to profit or loss:

Net gains in respect of cash flow hedges

Net gains in respect of cost of hedging

Net losses on investments in debt instruments measured at fair value through other comprehensive income

(12)

Tax on items that may be reclassified subsequently to profit or loss

(3)

Total items from continuing operations that may be reclassified subsequently to profit or loss

(9)

Other comprehensive income for the period, net of tax

(9)

(86)

Income taxes paid (refund) [abstract]

£ 56

£ (49)

[1]	Comparative amounts have been re-presented to reflect the classification of the FAA option within the UK Gas Transmission business disposal group.
[2]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Tax from continuing operations (Details) - GBP (£)
£ in Millions

6 Months Ended

12 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Mar. 31, 2023

Tax charge from continuing operations

£ (307)

£ (447)

^[1]

Average effective tax rate

22.40%

26.80%

24.40%

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Earnings per share (Details) - GBP (£)
£ / shares in Units, £ in Millions, shares in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

Basic earnings per share [abstract]

Profit after tax from continuing operations attributable to the parent

£ 1,063

£ 1,219

Profit after tax from discontinued operations attributable to the parent

Total profit after tax attributable to the parent

£ 1,128

£ 1,256

Basic earnings per share (continuing) (in GBP per share)

£ 0.288

£ 0.334

^[1]

Basic earnings per share (discontinued) (in GBP per share)

0.018

0.01

Basic earnings per share (continuing and discontinued) (in GBP per share)

£ 0.306

£ 0.344

^[1]

Weighted average number of shares - basic (in shares)

3,682

3,651

Diluted earnings per share [abstract]

Profit after tax from continuing operations attributable to the parent

£ 1,063

£ 1,219

Profit after tax from discontinued operations attributable to the parent

Total profit after tax attributable to the parent

£ 1,128

£ 1,256

Diluted earnings per share (continuing) (in GBP per share)

£ 0.287

£ 0.332

^[1]

Diluted earnings per share (discontinued) (in GBP per share)

0.018

0.01

Diluted earnings per share (continuing and discontinued) (in GBP per share)

£ 0.305

£ 0.342

^[1]

Weighted average number of shares - diluted (in shares)

3,700

3,668

[1]	Comparative amounts have been re-presented to reflect the classification of the Further Acquisition Agreement (the FAA option) as held for sale and within discontinued operations.

Dividends - Schedule of dividends (Details) - GBP (£) £ / shares in Units, £ in Millions	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Final dividend
Summary Of Dividends [Line Items]
Cash dividend paid (in GBP per share)	£ 0.3760	£ 0.3376
Cash dividend paid	£ 1,325	£ 1,119
Scrip dividend	£ 56	£ 114
Interim dividend
Summary Of Dividends [Line Items]
Cash dividend paid (in GBP per share)	£ 0.1784
Cash dividend paid	£ 488
Scrip dividend	£ 163

Dividends - Narrative (Details) - GBP (£) £ / shares in Units, £ in Millions	6 Months Ended	12 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Mar. 31, 2022
Summary Of Dividends [Line Items]
Dividends declared before financial statements authorised for issue (GBP per share)	£ 0.1940
Dividends declared before financial statements authorised for issue	£ 716
Final dividend
Summary Of Dividends [Line Items]
Cash dividend paid (in GBP per share)		£ 0.3760	£ 0.3376
Cash dividend paid		£ 1,325	£ 1,119
Scrip dividend		£ 56	£ 114

Fair value measurement - Schedule of assets and liabilities measured at fair value (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	£ 2,263	£ 3,052
Financial liabilities	(1,447)	(1,312)
Total	816	1,740
Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	1,007	1,764
Financial liabilities	0	0
Total	1,007	1,764
Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	751	810
Financial liabilities	(1,297)	(1,131)
Total	(546)	(321)
Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	505	478
Financial liabilities	(150)	(181)
Total	355	297	£ 223	£ 233
Financing derivatives
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(1,314)	(1,119)
Financing derivatives \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Financing derivatives \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(1,219)	(997)
Financing derivatives \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(95)	(122)
Commodity contract derivatives
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(123)	(174)
Commodity contract derivatives \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Commodity contract derivatives \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(78)	(134)
Commodity contract derivatives \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(45)	(40)
Contingent consideration
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(10)	(19)
Contingent consideration \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Contingent consideration \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	0	0
Contingent consideration \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial liabilities	(10)	(19)
Investments held at fair value through profit and loss
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	1,490	2,216
Investments held at fair value through profit and loss \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	1,007	1,764
Investments held at fair value through profit and loss \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Investments held at fair value through profit and loss \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	483	452
Investments held at fair value through other comprehensive income
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	388	407
Investments held at fair value through other comprehensive income \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Investments held at fair value through other comprehensive income \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	388	407
Investments held at fair value through other comprehensive income \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Financing derivatives
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	329	363
Financing derivatives \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Financing derivatives \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	309	341
Financing derivatives \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	20	22
Commodity contract derivatives
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	56	66
Commodity contract derivatives \| Level 1
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	0	0
Commodity contract derivatives \| Level 2
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	54	62
Commodity contract derivatives \| Level 3
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Financial assets	£ 2	£ 4

Fair value measurement - Narrative (Details) £ in Millions	Sep. 30, 2023 GBP (£) investment	Mar. 31, 2023 GBP (£)
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Borrowings \| £	£ 44,797	£ 42,985
Number of equity investments valued based on latest transaction price	15
Number of equity investments	33
Number of equity investments valued based on internal valuation process	18
At fair value
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Borrowings \| £	£ 38,354	£ 38,219

Fair value measurement - Schedule of impacts of reasonably possible changes in significant Level 3 assumptions (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Sep. 30, 2022
Financing derivatives \| +20 basis point increase in Limited Price Index (LPI) market curve
Disclosure of sensitivity analysis for actuarial assumptions [line items]
+20 basis point increase in Limited Price Index (LPI) market curve	£ (38)	£ (51)
Financing derivatives \| -20 basis point decrease in LPI market curve
Disclosure of sensitivity analysis for actuarial assumptions [line items]
-20 basis point decrease in LPI market curve	38	51
Financing derivatives \| +20 basis point increase between Retail Price Index (RPI) and Consumer Price Index (CPI)
Disclosure of sensitivity analysis for actuarial assumptions [line items]
+20 basis point increase between Retail Price Index (RPI) and Consumer Price Index (CPI)	36	17
Financing derivatives \| -20 basis point decrease between RPI and CPI market curves
Disclosure of sensitivity analysis for actuarial assumptions [line items]
-20 basis point decrease between RPI and CPI market curves	(33)	(16)
Commodity contract derivatives \| 10% increase in commodity prices
Disclosure of sensitivity analysis for actuarial assumptions [line items]
10% increase in commodity prices	15	35
Commodity contract derivatives \| 10% decrease in commodity prices
Disclosure of sensitivity analysis for actuarial assumptions [line items]
10% decrease in commodity prices	(15)	(36)
Commodity contract derivatives \| +10% market area price change
Disclosure of sensitivity analysis for actuarial assumptions [line items]
+10% market area price change	12	7
Commodity contract derivatives \| -10% market area price change
Disclosure of sensitivity analysis for actuarial assumptions [line items]
-10% market area price change	(11)	(7)
Other \| +50 basis points change in discount rate
Disclosure of sensitivity analysis for actuarial assumptions [line items]
+50 basis points change in discount rate	(8)	(9)
Other \| -50 basis points change in discount rate
Disclosure of sensitivity analysis for actuarial assumptions [line items]
-50 basis points change in discount rate	9	£ 10
Other \| +10% change in venture capital price
Disclosure of sensitivity analysis for actuarial assumptions [line items]
+10% change in venture capital price	30
Other \| -10% change in venture capital price
Disclosure of sensitivity analysis for actuarial assumptions [line items]
-10% change in venture capital price	£ (30)

Fair value measurement - Schedule of reconciliation of changes in Level 3 (Details) - GBP (£) £ in Millions	6 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Changes In Fair Value Measurement, Assets (Liabilities) [Roll Forward]
Financial assets (liabilities), beginning balance	£ 1,740
Financial assets (liabilities), ending balance	816
Level 3
Changes In Fair Value Measurement, Assets (Liabilities) [Roll Forward]
Financial assets (liabilities), beginning balance	297	£ 233
Net gains/(losses) through the consolidated income statement for the period	47	150
Purchases	1	(152)
Settlements	10	(8)
Financial assets (liabilities), ending balance	355	223
Financing derivatives \| Level 3
Changes In Fair Value Measurement, Assets (Liabilities) [Roll Forward]
Financial assets (liabilities), beginning balance	(100)	(187)
Net gains/(losses) through the consolidated income statement for the period	25	76
Purchases	0	(133)
Settlements	0	0
Financial assets (liabilities), ending balance	(75)	(244)
Gains (losses) recognized in P&L	25	93
Commodity contract derivatives \| Level 3
Changes In Fair Value Measurement, Assets (Liabilities) [Roll Forward]
Financial assets (liabilities), beginning balance	(36)	44
Net gains/(losses) through the consolidated income statement for the period	(4)	44
Purchases	(10)	(56)
Settlements	7	(4)
Financial assets (liabilities), ending balance	(43)	28
Gains (losses) recognized in P&L	(15)	(23)
Other \| Level 3
Changes In Fair Value Measurement, Assets (Liabilities) [Roll Forward]
Financial assets (liabilities), beginning balance	433	376
Net gains/(losses) through the consolidated income statement for the period	26	30
Purchases	11	37
Settlements	3	(4)
Financial assets (liabilities), ending balance	£ 473	£ 439

Net debt - Schedule of components of net debt (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023
Disclosure of detailed information about financial instruments [line items]
Cash and cash equivalents	£ 227	£ 163
Current financial investments	1,680	2,605
Borrowings and bank overdrafts	(44,797)	(42,985)
Financing derivatives	(985)	(756)
Net debt (net of related derivative financial instruments)	(43,875)	(40,973)
Derivative liabilities	1,052	864
Derivatives \| Capital expenditure
Disclosure of detailed information about financial instruments [line items]
Derivative liabilities	£ 4	£ 4

Net debt - Schedule of balance sheet allocation of derivative balances (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023
Disclosure of detailed information about financial instruments [line items]
Derivative financial assets	£ 385	£ 429
Derivative financial liabilities	(1,437)	(1,293)
Financing derivatives	(1,052)	(864)
Financing derivatives
Disclosure of detailed information about financial instruments [line items]
Derivative financial assets	329	363
Derivative financial liabilities	(1,314)	(1,119)
Financing derivatives	(985)	(756)
Commodity contract derivatives
Disclosure of detailed information about financial instruments [line items]
Derivative financial assets	56	66
Derivative financial liabilities	(123)	(174)
Financing derivatives	£ (67)	£ (108)

Pensions and other post-retirement benefit obligations - Schedule of defined benefit plan recognised in balance sheet (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023
Disclosure of defined benefit plans [line items]
Other post-employment liabilities	£ (67)	£ (69)
Net defined benefit asset	1,737	1,951
Assets	2,352	2,645
Liabilities	(615)	(694)
Funded obligations
Disclosure of defined benefit plans [line items]
Present value of obligations	(17,502)	(18,934)
Fair value of plan assets	19,570	21,246
Funding surplus/(deficit)	2,068	2,312
Unfunded obligations
Disclosure of defined benefit plans [line items]
Present value of obligations	£ (264)	£ (292)

Pensions and other post-retirement benefit obligations - Schedule of key actuarial assumptions (Details)	Sep. 30, 2023	Mar. 31, 2023
UK
Disclosure of defined benefit plans [line items]
Discount rate – UK past service	5.55%	4.80%
Rate of increase in RPI – UK past service	3.19%	3.17%
US
Disclosure of defined benefit plans [line items]
Discount rate – US	5.70%	4.85%

Pensions and other post-retirement benefit obligations - Narrative (Details) - GBP (£) £ in Millions	6 Months Ended
	Sep. 30, 2023	Mar. 31, 2023
Disclosure of defined benefit plans [line items]
Net defined benefit asset	£ 1,737	£ 1,951
Increase in net defined benefit asset	(214)
Net actuarial losses	263
Actuarial losses related to asset performance	(1,754)
Actuarial gain related to changes in actuarial assumptions	1,491
UK
Disclosure of defined benefit plans [line items]
Actuarial losses related to asset performance	(1,155)
Actuarial gain related to changes in actuarial assumptions	793
Funding surplus/(deficit)	1,377	1,672
US
Disclosure of defined benefit plans [line items]
Actuarial losses related to asset performance	(599)
Actuarial gain related to changes in actuarial assumptions	698
Funding surplus/(deficit)	£ 975	£ 973

Commitments and contingencies (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023
Subclassifications of assets, liabilities and equities [abstract]
Energy purchase commitments	£ 13,824	£ 19,194
Contractual capital commitments	£ 3,218	£ 2,936

Exchange rates (Details)	6 Months Ended		12 Months Ended
Exchange rates (Details)	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2023
Foreign exchange rates [abstract]
Closing rate applied at period end	1.22	1.12	1.23
Average rate applied for the period	1.25	1.21	1.22

Additional disclosures in respect of guaranteed securities - Narrative (Details) - GBP (£) £ in Millions		6 Months Ended
	Oct. 29, 2007	Sep. 30, 2023
National Grid plc and Niagara Mohawk Power Corporation combined
Disclosure of information about consolidated structured entities [line items]
Proceeds from issuing shares		£ 23
National Grid Gas Plc
Disclosure of information about consolidated structured entities [line items]
Preferred shares issuance rate	3.60%
British Transco Finance Inc.
Disclosure of information about consolidated structured entities [line items]
Preferred shares issuance rate	3.90%

Additional disclosures in respect of guaranteed securities - Disclosure of Combined Statement of Financial Position (Details) - GBP (£) £ in Millions	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022
Disclosure of information about consolidated structured entities [line items]
Non-current assets	£ 86,550	£ 83,531
Current assets	7,697	9,166
Current liabilities	(8,279)	(9,130)
Non-current liabilities	(56,488)	(54,005)
Net assets	29,480	29,562
Equity	29,480	£ 29,562	£ 25,957	£ 23,856
Other subsidiaries
Disclosure of information about consolidated structured entities [line items]
Non-current assets	126
Current assets	15,557
Current liabilities	(6,893)
Non-current liabilities	(2,080)
Investments in subsidiaries reported in separate financial statements	14,480
National Grid plc and Niagara Mohawk Power Corporation combined
Disclosure of information about consolidated structured entities [line items]
Non-current assets	12,033
Current assets	1,526
Current liabilities	(1,263)
Non-current liabilities	(13,703)
Net assets	5,303
Equity	£ 5,303

Additional disclosures in respect of guaranteed securities - Disclosure of Combined Income Statement (Details) - GBP (£)
£ in Millions

6 Months Ended

Sep. 30, 2023

Sep. 30, 2022

^[1]

Disclosure of information about consolidated structured entities [line items]

£ 8,489

£ 9,444

1,985

2,239

National Grid plc and Niagara Mohawk Power Corporation combined

1,064

£ 1,219

^[2]

Disclosure of information about consolidated structured entities [line items]

1,594

Operating costs

(1,330)

Other income and costs, including taxation

264

(51)