A SECRET e-mail from the constructor of Wembley stadium allegedly proposed to "f***" Cleveland Bridge after a multi-million pound row broke out between the companies.

Wembley's main contractor Multiplex, and Darlington steel firm Cleveland Bridge UK (CBUK), are embroiled in a court case after Cleveland walked off the project last year.

And CBUK claims in court papers that Multiplex launched a plan, which it allegedly referred to as the Armageddon Plan, to put the Darlington firm out of business and deal with any potential court action after the Wembley project was finished.

Cleveland Bridge submitted its defence and counter-claim against Multiplex to the Court of Technology and Construction last month.

Its case, in part, hinges on what CBUK claims is a confidential e-mail from Multiplex's project director to its former UK managing director, which highlighted its course of action as "plan b: CBUK fixed and f*** them later".

With £50m at stake in the court case, Cleveland Bridge has accused Multiplex of attempting to put it out of business by handing it a lawsuit at a time when the company's sole business was the Wembley stadium.

Cleveland's court claims are that Multiplex needed its specialist expertise to construct the stadium's iconic arch, but then the Australian company wanted CBUK off the project.

Cleveland left the Wembley project in August 2004, and was replaced by Dutch steel fabricator Hollandia.

Despite problems after leaving the contract, which included job losses in Darlington, Cleveland Bridge was supported by its Saudi Arabian parent company, which has bankrolled the court action.

Both companies declined to comment.