RNS Number:9637R
Marconi Corporation PLC
12 November 2003


                                                                Press enquiries:
                     Joe Kelly, tel: 0207 306 1771; email: joe.kelly@marconi.com
                   David Beck, tel: 0207 306 1490; email: david.beck@marconi.com
                                                             
                                                             Investor enquiries:
             Heather Green, tel: 0207 306 1735; email: heather.green@marconi.com

                            Marconi Corporation plc
                  SALE OF INTEREST IN CONFIRMANT JOINT VENTURE

LONDON - November 12, 2003 - Marconi Corporation plc (London: MONI and Nasdaq:
MRCIY) today announces that it has sold its 50 percent interest in Confirmant
Limited for over #4 million in cash to Oxford GlycoSciences, a wholly owned
subsidiary of Celltech Group plc. Confirmant is a joint venture set up by
Marconi and Oxford GlycoSciences in June 2001. The purchase price represents an
apportionment of Confirmant's available cash resources between Marconi and
Oxford GlycoSciences.

Marconi will pay the gross cash proceeds into the Mandatory Redemption Escrow
Account and the cash will be used, in due course, to fund a further partial
redemption of the Group's Junior Notes. Mike Parton, chief executive, said: "In
addition to the cash proceeds we will receive for disposing of our interest in
what is a non-core joint venture, we eliminate an annual non-cash loss to the
Group of some #5 million."

ENDS/...

About the Mandatory Redemption Escrow Account (MREA)
When the balance of the MREA reaches US$30 million, this triggers a mandatory
partial redemption of Marconi's Junior Notes at 110 per cent of par value.

About Marconi Corporation plc
Marconi Corporation plc is a global telecommunications equipment, services and
solutions company. The company's core business is the provision of innovative
and reliable optical networks, broadband routing and switching and broadband
access technologies and services. The company's customer base includes many of
the world's largest telecommunications operators.

The company is listed on the London Stock Exchange under the symbol MONI and
Nasdaq under the symbol MRCIY. Additional information about Marconi Corporation
can be found at www.marconi.com.

Copyright (c) 2003 Marconi Corporation plc. All rights reserved. All brands or
product names are trademarks of their respective holders.

This press release contains forward-looking statements with respect to products,
partners, customers, future growth and other matters. Please refer to the Form
20-F report and Form 6-K reports filed by Marconi Corporation plc with the
United States Securities and Exchange Commission for a discussion of risks that
could cause actual results to differ materially from such statements.




                      This information is provided by RNS
            The company news service from the London Stock Exchange

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