Farrells has walked away from one of the most contentious projects in London after committing 10 years to working on schemes for the site, the AJ can reveal.
The practice left the Stanhope team astonished last week when it suddenly resigned from the controversial South Kensington tube station redevelopment scheme.
The office is also expected to take with it Panter Hudspith, Munkenbeck + Marshall and Birds Portchmouth Russum, all of whom were working with it on the proposals for the highly significant site.
Farrells' proposals - which are currently being touted by Stanhope to locals and planners at Kensington and Chelsea council - are the latest attempt to find a commercial scheme that would fund the renovation of the historic tube station.
They would see the development of a large site above and around the station, including offices, residential and retail elements (pictured).
This is not the first time the site has hit the headlines.
The last Farrells planning application, rejected in December 2003, was one of the chief reasons behind the problems faced by CABE when it was subject to a Conflict of Interest Audit last summer. Conservationists and locals had complained to the government that the design watchdog - which gave the Farrells and Stanhope scheme the thumbs up - was chaired by Stanhope boss Stuart Lipton.
After these proposals were thrown out by planners, Stanhope sent Farrells back to the drawing board and the practice recruited the other three offices to collaborate on fresh plans for the site. They were also set a new brief after the existing building was listed in August 2004.
Less than 24 hours before these new designs were set to be presented to planners and locals last Friday, Stanhope received a letter from Farrells directors, withdrawing from the project.
The reasons for this sudden departure are currently unclear, but one long-term observer said that the office felt it was 'somehow being undermined on the project'.
But it is certain that local campaigners, who have objected to every scheme proposed for the site by Farrells over the last decade, will be delighted by the resignation.
'It has been our opinion that since the station was listed there should have been a new architect on the project, ' Sophie Blain, chairman of local campaign group the Brompton Association said.
She also said she has the support of the Kensington Society and the Chelsea Society in the matter.
'We need to get an architect on board that will work within the sensitivity of the building, ' she added.
It is understood that Stanhope is expected to appoint a new architect for the project imminently.