Contract workers who staged walkouts at a number of U.K. energy plants this week are returning to work Thursday, following a deal to withdraw 40 non-U.K. workers from a project at South Hook liquified natural gas terminal in Wales. Netherlands-based industrial services company Hertel has agreed to withdraw the foreign labor after U.K. workers demanded it offer the jobs to local people.

The dispute at South Hook, in Milford Haven, Wales, Europe's biggest LNG terminal, triggered walkouts by hundreds of contract workers across other U.K. energy facilities Tuesday and Wednesday, echoing similar protests in January and February.

"After lengthy negotiations between the company and GMB [union], a framework has been reached which will fully restore the written agreement on the site regarding the use of local labor," said Paul Kenny, GMB general secretary, on the unofficial dispute at South Hook.

Meanwhile, ConocoPhillips (COP) spokeswoman Nina Krogh-Nielsen confirmed that the contract workforce at the 221,000 barrel-a-day Humber refinery in eastern England had also returned to work and that previous action hadn't effected refinery operations.

Wendy Goldsworthy, spokeswoman for Dragon LNG terminal in Wales, said in an e-mailed statement to Dow Jones Newswires that its contract workers were back at their posts Thursday.

Total SA's (TOT) spokesman at the Lindsey refinery in eastern England, Iain Hutchison, said a meeting earlier Thursday concluded in an agreement that their workers will return to work Friday.

Royal Dutch Shell's (RDSB) spokeswoman for the Stanlow refinery in northwest England, Sally Hepton, said: "All workers have been back to work since yesterday [Wednesday], no new developments, operations running as normal." The Stanlow contract workers staged a walkout Tuesday.

Most of the contractors working at RWE AG's (RWE.XE) Aberthaw power station in Wales have also returned to work Thursday, the company said.

Company Web site: http://www.conocophillips.co.uk

Company Web site: http://www.southhooklng.co.uk

Company Web site: http://www.dragonlng.co.uk

Company Web site: http://www.total.co.uk

Company Web site: http://www.dragonlng.co.uk

Company Web site: http://www.shell.co.uk

Company Web site: http://www.scottish-southern.co.uk

-By Angela Henshall and Lananh Nguyen, Dow Jones Newswires; +44 (0)20 7842 9285; angela.henshall@dowjones.com (Reza Amanat and Selina Williams contributed to this story.)