Towering building site cranes stood silent yesterday as operators launched a first wave of strike action on pay — immediately forcing bosses to the negotiating table.

Members of construction union Ucatt struck a defiant tone on picket lines in London and Sheffield aimed at getting employer HTC to agree to talks.

Strikers at the big Nova Victoria site in the capital caused huge disruption by blocking deliveries shortly after the start of a critical operation to install a load-bearing block.

Hours after the first of three Friday walkouts had begun, bosses agreed to Tuesday talks.

Shop steward Simon Pantry estimated that the dispute had already hit HTC with “millions and millions of pounds of aggro.”

At its heart is growing fury at the firm’s refusal to raise wages after a 30 per cent cut during the 2009 slump.

A 3 per cent offer was rejected by Ucatt members in August, before being forcibly imposed a month ago.

HTC workers on booming construction sites in London receive basic pay of £9.50 an hour but are demanding £13 for their “dangerous and safety critical” role operating massive cranes.

“When it goes wrong with one of those, it goes horrifically wrong,” said Mr Pantry.

He described the strikers’ mood as “very high, very ebullient,” adding: “They are prepared to go out next week and the week after and keep going out every week.”

Union membership at HTC has risen sharply during the dispute, from just under half to 96 per cent.

Ucatt general secretary Steve Murphy said: “The strike action was called after HTC failed to make a reasonable offer and Ucatt remains committed to a negotiated settlement.

“Ucatt deeply regrets HTC’s decision to bar crane drivers involved in strike action today from working this weekend.

“This decision is entirely counterproductive. It simply heaps more misery and delays on other construction workers and contractors.

Mr Murphy lauded the strikers’ resolution in the face of management bullying, saying the strike was “absolutely solid.

“HTC now must understand the anger of the workforce and make a sensible, realistic offer,” he added.