This morning it revealed that remedial works to fix the problems will cost at least £20m, but warned it was still assessing the full impact of fixing weld issues.

While Severfield did not reveal where the bridge projects are, it is understood that they are structures on the giant HS2 project.

The extent of Severfield’s problems were revealed for the first time this morning when the firm reported a £6m loss in the first half on sales up 17% at £252m.

In a statement, Alan Dunsmore, chief executive officer, said: “Since the publication of the 2024 results, the group identified some bridge structures which were not in compliance with the client’s weld specification requirements, predominantly relating to twelve bridge projects that are either ongoing or were completed over the past four years.

“The issues all arise out of a particular bridge specification and related sub-optimal choices of welding procedures, exacerbated by limitations in the specified weld testing regime for these projects.”

He said: “A comprehensive review is currently being undertaken by the group, in conjunction with its affected clients, relevant industry authorities and insurers to fully understand the extent of the actions required to resolve the issue, which has not affected the safety of any operational bridges.

“Notwithstanding this, we are continuing our work on ongoing road and rail bridges for a variety of clients, which we are confident will meet the required specification.”

So far Severfield has spent £7.1m on testing and remedial works and expects to incur a further £13.3m cost on eight of the projects.

Severfield added that it still needed to agree solutions on four of the remaining bridge projects where weld testing is ongoing.

As a result, he warned, Severfield was unable to quantify the full extent of its possible exposure based on current information.

“All amounts will be kept under review until our assessment of all affected structures has been concluded.

“The group will be pursuing all potential recoveries from third parties, including insurance, with preliminary indications suggesting a good prospect of insurance recovery, albeit not yet with the level of certainty required for such recovery to be recognised under accounting standards.”