HTC Wolffkran and Unite held six hours of discussions chaired by conciliation service Acas this week.

But the union dismissed a revised pay  offer of a 3% increase and more holidays as “derisory” as it prepared to hold a strike ballot.

Acting national officer for construction Jerry Swain said: “The company’s latest pay offer is frankly pathetic and way below our members’ expectations whose pay has fallen in real terms in the last decade.

“Unite will be preparing to launch a full industrial action ballot.

“Our members are not going to accept a below inflation offer from a company which has seen profits soar. This offer represents a cut in real terms to our members’ pay.”

Major sites where HTC Wolffkran is currently operating include: the Tottenham Hotspur football stadium, the Westfield shopping centre in Shepherds Bush, the BBC TV centre at White City and the new Goldmans Sachs building in Farringdon.

Swain added: “The company needs to understand that crane drivers undertake a highly skilled job in stressful, difficult conditions and want to be properly rewarded for their work.

“The only way that HTC can avoid major industrial action is if the company returns to the negotiating table with a substantially improved offer.

“If strike action occurs it will result in major industrial disruption which will have a massive effect on all sites where the company operates.”