Aukett Fitzroy Robinson and Bucknall Austin behind the redevelopment of Sir Basil Spence's Queen Anne's Gate

Aukett Fitzroy Robinson and Bucknall Austin are the architect and cost consultant behind the £100m redevelopment of the Queen Anne's Gate Home Office building in central London, Building can reveal.

Originally designed by Sir Basil Spence, the architect of Coventry Cathedral, the 29-year-old building is one of the most imposing in the Westminster village. Plans for its redevelopment have been closely guarded after criticism of the cost of the PFI contract in the national media two years ago.

However, Building understands that later this month hoardings will be erected revealing that Bucknall Austin and Aukett Fitzroy Robinson as part of the project team.

A source close to the project said: "Bucknall Austin and Aukett Fitzroy Robinson have been working on this behind the scenes for some time."

The PFI deal emerged when the Home Office decided to leave its famous headquarters for a development designed by Terry Farrell and Partners in nearby Marsham Street.

As part of the deal, developer Land Securities took over the Queen Anne's Gate tower block when Home Office staff vacated it last year.

They have been working behind the scenes for some time

Source close to the project

The 51,000 m2 building, which is to reopen late next year, will be run and maintained by Land Securities for its new occupier, the Department of Constitutional Affairs. The DCA has a lease until 2026.

Lead contractor Skanska has been working on the building since Christmas, largely on demolition .

In 2004, the Daily Mail criticised the lord chancellor, Lord Falconer, for "lavishing" £150m on the PFI, including payment for maintenance costs during the lease, despite the DCA having one of the smallest budgets among government departments.

The news of Bucknall Austin's appointment emerges a week after Building revealed that Sir Digby Jones, currently director-general of the CBI, will join the consultant at the start of May as non-executive director.