The employers were due to meet with Unite officials in Glasgow last Friday to discuss the plans but the talks were cancelled.

Unite national officer, Bernard McAulay said: “These employers are behaving completely irresponsibly. They have now withdrawn from discussions with Unite that could lead to a way out of this mess.”

Plans to replace the long-standing JIB pay and conditions deal with a new agreement known as BESNA have sparked widespread opposition among sections of the workforce.

Unite is currently organising a strike ballot at Balfour Beatty Engineering Services which closes on November 29.

McAulay said: “These employers should realise that there will be no winners in a full-blown confrontation with their workers who are quite rightly wanting to defend their livelihoods.”

An HVCA spokesman said: “Last week’s meeting did not take place as it is standard industrial relations protocol not to hold meetings with union officials whilst under the threat of a strike ballot or while such a ballot is underway.”

Unite is now calling for Acas to be brought in to resolve the dispute.