The raiders got away with around 80 tonnes of structural steel in the dead of night from the yard of paint specialist Vale Protective Coatings, based near Langar Airfield.

The steel was due to be treated with intumescent paint before being sent on to major building jobs.

A project source told the Enquirer much of the steel was destined for Laing O’Rourke’s new cancer block for Guy’s Hospital in London.

But there were also smaller amounts due to go out for a project at London’s King’s Cross goods yard development and Shepherd Construction’s Wellington Place scheme in Leeds.

Nottinghamshire police said the burglary took place sometime between last Saturday evening and 5.45am on Sunday.

Eight trailers laden with structural steel were driven out of the yard as well as two JCB telehandlers and a skidsteer.

Police launched a helicopter search of the area soon after the alert was raised on Sunday morning in the hope of spotting the eight trailers on the move but failed to locate the thieves.

Ongoing investigations this week suggest the gang may have stolen several lorries in Hull to pull off the job and police are hopeful of arrests after recovering a trailer in a field.

A source from Vale said: “We are stunned by what has happened. The gang had to break through several heavy-duty security gates.

“They must have had five or six lorries to drive off with all the steel. It was clearly a professional gang that had targeted us.”

It is assumed the steel was stolen for scrap but would only probably fetch around £8,000, compared to its fabricated worth of around £120,000. The stolen plant would have been worth considerably more to the gang on the blackmarket.