Royal Opera House electricians want a golden handshake to finish the project following Jubilee Line Extension contractor Balfour Beatty/Amec’s decision to pay a finishing bonus to civils workers.

Electricians on the beleaguered £220m project have stopped all overtime and said the bonus deal between themselves and M&E contractor Balfour Kilpatrick was null and void.

Electricians claimed Balfour Kilpatrick had refused to honour the agreement, which would have guaranteed them an additional 10 hours pay a week, and at a heated meeting last Friday voted unanimously to scrap the deal.

They now plan to work a 37-hour week and warned that strike action was a strong possibility if a deal was not thrashed out in the next week.

One electrician said: “Out of 250 sparks, only 30 have earned the agreed bonus. They need to come up with a new deal with new incentives to get this project moving, and a termination payment would be a good start.” Site sources claimed that Balfour Kilpatrick project director John Moore visited the site on Tuesday to discuss the electricians’ grievances and told them it did not matter if the opera house missed its December deadline.

Balfour Kilpatrick and construction manager Schal refused to comment on the dispute. However, Peter Rogers, director of developer Stanhope, which is advising on the scheme, said: “We’ll do what we can and hopefully common sense will sort things out.”