Consultant set to be held liable for up to 40 glazed panels that have been replaced at MPs new offices.

Multidisciplinary practice Ove Arup Partnership is facing a bill of at least £250 000 for glazing problems at the new parliamentary building, Portcullis House.

It has emerged that Arup Facades Engineering, part of Ove Arup Partnership, will be held liable for defects in the glazing system after a number of panes cracked and had to be replaced.

The news comes during a difficult period for the world-renowned consultant, which attracted intense media attention following problems with movement on the Millennium Bridge at London’s Bankside.

A spokesperson for Arup Facades said the issue of liability for the glazing had not yet been decided and referred all enquires to the Parliamentary Works Directorate. A spokesperson for the Parliamentary Works Directorate, which is responsible for the construction of the building, also said liability had not yet been decided.

However, project insiders said Arup Facades would be told within the next four to five weeks that it must accept liability for the problem. The cracking was first detected in December.

Forty of the giant 2 × 1 m double-glazed panels have since been removed from the curved corner facade over the past 12 weeks and replaced with panes of a different specification after 16 were found to be defective.

The original system comprised one thick pane of glass joined to a thin pane. It is thought that the cracking was caused by the excessive load placed on the thin pane by the thick one.

It is understood that Arup Facades initially felt the problem was caused during the installation of the glazing, which was carried out by Anglo-German cladding contractor Seele Alvis Fenestration.

One project insider said a series of “very heated discussions” had taken place between Arup Facades, the cladding contractor and the Parliamentary Works Directorate following Building’s revelation of the problem in March this year.

The insider said: “It’s a design problem and [Arup Facades] know it. The entire fenestration system was designed by Arup; the cracking is unrelated to the installation.”

He added: “They kept insisting it’s not their problem, but the bottom line is that it is down to them. They are liable.”

It was originally thought that the problem would cost about £250 000 to rectify. However, insiders now say this is likely to rise, as it has involved additional work for contractors, which are fully occupied ensuring that the project is completed on time for its opening.

Portcullis House is expected to be officially opened to MPs next week.