The Enquirer understands that bolts are having to be replaced across the top four floors of the 12-storey building.

Sir Robert McAlpine and US partner B L Harbert are main contractors on the job where Severfield is steelwork contractor.

A site source told the Enquirer: “The problems are on the top floors and could involve as many as 33,000 bolts.

“It will take around eight weeks to replace the bolts.”

It is understood that the bolts on the upper four floors were sourced from America by Harbert while the bolts below that were sourced domestically.

Another site source said: “It will disrupt operations like concrete floor pours on the upper levels while this is sorted out but they will try and reschedule work to avoid delays.”

A Sir Robert McAlpine statement said: “We can confirm that some bolts are being replaced. This does not affect the overall project schedule at all.”

Severfied Rowen was hit by bolt problems on the Cheesegrater tower in the City of London where an ongoing replacement programme is costing an estimated £6m.

Remedial work involving the replacement of all bolts at risk is continuing to the end of this year in the City.

Talks are still ongoing with the Cheesegrate’s project team  over where the liability for the costs of the programme should rest.

Severfield declined to comment.

Bolt problems have hit the top four floors of the job/Picture courtesy of the US Embassy