Steel erectors are set to step up pressure over pay by banning overtime on London sites from 20 September.

Projects likely to be hit include the Millennium Dome, HSBC’s Canary Wharf headquarters, the Merrill Lynch building in the Square Mile and St Catherine’s House in Kingsway, central London.

The workers, who staged an unofficial strike last month, want a London weighting allowance of £1 an hour reintroduced. It was was taken away during the recession of the early 1990s.

A spokesman for the erectors said they were disappointed by the lack of support from the AEEU, which has said an overtime ban was unnecessary.

A spokesman for the erectors said: “This is our last chance to get a better deal for the future. Employers are only going to listen while these millennium deadlines exist, and if the union won’t act, then we’ve got to act ourselves.”

AEEU national officer Paul Corby said: “The national agreement [governing steel erectors’ pay] is under review, and because of the volatility with the erectors I have written to steel contractors and told them I would like to enter discussions on the issue.”

Labour problems with erectors also erupted on London’s Ferris wheel, the British Airways London Eye, last week after British workers employed by labour agency Malla demanded pay parity with Dutch employees of Dutch steel specialist Hollandia.

Eight Malla steel erectors were laid off by construction manager Mace on Tuesday, two days before the wheel was scheduled to be raised into position.

Mace deputy chairman Ian Wylie denied that labour problems were the reason for the lay-off and that Mace had given the men a £3000 termination payment. Malla was unavailable for comment.

Wylie said: “It’s just a normal rundown of staff. There’s been an amicable discussion and the men were given one week’s pay and an extra couple of days’ pay. It was not connected to industrial action and it is not a completion bonus.”