Contract workers who staged walkouts at a number of UK 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.

Industrial services company Hertel has agreed to withdraw the foreign workers after U.K. workers demanded it offer the jobs to local people.

The dispute at the South Hook LNG terminal at Milford Haven, Wales, triggered walkouts by hundreds of contract workers across 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.

Spokeswoman for ConocoPhillips (COP) Nina Krogh-Nielsen confirmed the contract workforce at the 221,000 barrel-a-day Humber Refinery had also returned to work, and that previous action has not effected refinery operations.

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

-By Angela Henshall and Lananh Nguyen, Dow Jones Newswires; +44 (0)20 7842 9285; angela.henshall@dowjones.com