Architect Terry Farrell and Partners has been parachuted in by Southwark council to help rethink the embattled Potters Fields scheme next to the London mayor’s headquarters.

However, the boss of site developer Berkeley Homes said the final designer of the new scheme was yet to be chosen.

The 386-home mixed-use scheme on the south bank of the Thames had stalled because Southwark council, which owns half the site, opposes the current design, by Ian Ritchie Architects.

Last week Southwark council announced it was preparing to sign a “co-operation agreement” with Berkeley on 31 March in order to produce a “jointly agreed proposal for a new development”.

Southwark lost a planning appeal over the scheme in 2005, which ruled that Berkeley’s scheme of eight towers of up to 18 storeys could go ahead. However, as part-landowner, the council was able to block development from starting.

In response, mayor Ken Livingstone threatened to compulsorily purchase the site from Southwark.

We’d obviously much prefer it to be done through negotiation

GLA spokesperson

A spokesperson for the Greater London Authority said Farrell had been brought in on an interim basis by Southwark. He said: “They are keen to put a fresh application together with a fresh design.”

The spokesperson said: “We’d obviously much prefer it’s done through negotiation [than through a compulsory purchase order]. If we can produce a rapid alternative then it’s a very satisfactory outcome.”

Tony Pidgley, the chief executive of Berkeley, said the firm would interview a number of architects to decide who will carry out the final design.