Colonel Ross (Guy Dolman)'s office at the north eastern corner Whitehall, overlooking Trafalgar Square - used in three Harry Palmer spy films, starring Michael Caine: The Ipcress File (1965), Funeral in Berlin (1966) and Billion Dollar Brain (1967).
See the Harry Palmer Moviesite and Ipcress file film locations for more details:
GPS grid coordinates:
Latitude: (WGS84) N51:30:25 ( 51.507063 )
Longitude: (WGS84) W0:07:37 ( -0.127033 )