The old headquarters of the Abbey National in Baker St is currently being converted into a block of luxury apartments and the local council stipulated that the bell tower had to be retained in the scheme of the new development. The work on the building, which incorporates the famous (and fictitious) address of Sherlock Holmes's lodging house at number 221b Baker St, has involved complex hydraulic propping by Bill Boley Ltd to prevent the tower supports splaying out in the clay subsoil. Steel girders have been set at an angle into the ground and hydraulic jacks have been used to pre-tension the outer support frame of the building.