It also revealed the firm is in talks with the main contractor, client and engineer on the building to thrash out who should foot the final bill.

Three bolts have failed on the 122 Leadenhall leading to an extensive replacement programme that is not due to complete until the end of 2015.

Severfield said it had incurred almost £1m of costs to date relating to bolt replacement works.

This programme is being undertaken in conjunction with British Land, Laing O’Rourke and Arup and is likely to continue until the end of the calendar year.

Client British Land has limited it comments about the scale of the problems to saying the programme amounts to replacing “a number of bolts”.

In January bolt supplier Andrews Fasteners fell into administration effectively meaning that any liability for claims disappeared with the firm.

Since then the business assets of the fastener supplier were bought by AFC Products, which subsequently changed its name to Andrews Fasteners under the control of Michael Carey, a former director of the original company.

A statement from Severfield said: “While these works progress, all parties continue discussions to agree where the liability for the costs of the programme should rest.

“The group’s costs are being regarded as exceptional and will not impact our underlying operating profit for the current year.”