Leaders of the Unite union claim Balfour and its fellow M&E clients have walked away from an Acas-brokered deal to resolve the long running dispute over changes to pay and conditions in the industry.

Workers voted in favour of industrial action at Balfour last month but the vote was challenged on a series of technicalities by the contractor.

The union said: “Unite is now left with no choice, other than to press ahead on with the re-ballot of its members at BBES.”

National officer, Bernard McAulay said: “Unite is hugely disappointed that the employers have not acted on our proposals to find a peaceful solution to the current dispute in the construction industry.

“Unite members at BBES originally voted overwhelmingly for strike action, but this was thwarted by legal technicalities. Unite will now re-ballot BBES in the New Year.”

A statement from the employers body HVCA said:  “The seven contractors and HVCA and are disappointed that Unite has announced plans for another strike ballot.

“We maintain that Unite’s decision is not in the best interests of their members, the workforce or the construction industry as a whole.

“All of the 6,000 employees who have been asked to sign up to the new Building Engineering Services National Agreement (BESNA) have received contracts from the seven contractors.

“Some of these workers have already accepted their contracts and returned them to their employers.

“We hope that the remaining employees can spend some time during the Christmas holiday reading through all the facts and details concerning the BESNA.

“The BESNA terms and conditions will come into effect during the last week in March and the first week of April 2012.

“The HVCA, supported by the contractors, hope to re-engage with Unite in early January in order for the union to play a key part in participating in the new agreement.”