The Grade I listed 55 Broadway building above St. James’s Park Tube station will be converted once its staff relocate in 2015.

The scheme forms part of a drive by transport chiefs to raise more than £1bn.

TfL said the building was no longer fit for purpose and has issued a tender inviting architects to submit proposals for converting the building into residential accommodation.

TfL looked at every potential option for the building with office, hotel and residential uses all being considered.

It said a residential led development would deliver the best value for fare and taxpayers, but also be the most suitable option for the iconic building to maintain its internal and external heritage.

Mike Brown MVO, Managing Director, London Underground and London Rail at TfL, said: “We recognise the historic features of our Grade I listed building, 55 Broadway, and we need to carefully ensure that any future use enhances its features.

“This tender is seeking architects who are used to working with heritage buildings.

“We take our responsibilities for our heritage assets extremely seriously. We also have a responsibility to fare and taxpayers to make sure that any redevelopment of 55 Broadway is a commercial success, with all proceeds reinvested in London’s transport network to deliver increased and improved services.’

In recognition of the significance of the building, TfL will be leading the planning application and the listed building approval process, rather than engaging with an external developer at this stage.

TfL expects to appoint the architects in October.