Construction work at Hinkley Point C could be delayed after unions threatened to strike in a dispute over bonus pay.
The GMB and Unite unions have accused contractors of failing to pay the bonuses predicted in the construction agreement for the new nuclear plant in Somerset.
The unions argue that the rate offered by the BYLOR consortium – made up of Bouygues TP and Laing O’Rourke – is not sufficient to attract the calibre of workers needed to ensure that the £18 billion project is built on time.
They said the other employer Keir Bam is not currently at the negotiating table.
“This poor offer is unacceptable under all of the circumstances and our members came to Hinkley Point under the belief that they would receive excellent pay and bonuses,” said Unite regional officer, Tim Morris.
“The employers think they can do this on the cheap by offering a derisory bonus rate, but the workers consider it to be completely inadequate to attract and hold onto the skilled workforce necessary.”
GMB regional officer Adie Barker added: “GMB members are not prepared to accept this derisory offer on bonus payments that also threatens health and safety standards on site.”
The unions will hold a consultative ballot on industrial action among the 700-strong workforce preparing the groundworks for the nuclear plant between 2 and 5 May.
Rob Miguel, chair of the Hinkley Point C joint union committee, said: “If the consultative ballot eventually leads to a full-scale industrial action ballot, we could be looking at delays to the construction at Hinkley Point, which will be very expensive for the employers as hired-in plant and machinery will be lying idle.
“The scheme has already been plagued by delays over its financing and can’t afford any further interruptions.”
He urged contractors to get “back around the table” with union officials so a fair deal can be reached and work can continue.
A spokesman for plant developer EDF Energy responded: “We are committed to a continuing dialogue on this issue with our contractor and trade union partners. Discussions are ongoing and our intention is to reach a mutually acceptable outcome.
“We have a strong partnership in place with the trade unions based on a set of landmark agreements that include pay and productivity. We share a commitment with them and our contract partners to provide high quality employment standards, alongside the best standard in health, safety, quality and productivity.”
Last month EDF Energy revealed that the first concrete had been poured for a permanent structure at Hinkley Point C.