The building, which has a prominent mansard roof, was completed around 1924, when it became the main operating base for the Secret Intelligence Service.

[1][a] During the Second World War it had a brass plaque identifying it as the offices of the "Minimax Fire Extinguisher Company".

[1] Sir Stewart Menzies, Chief of the Secret Intelligence Service, had access to a tunnel, which connected 54 Broadway to his private residence in Queen Anne's Gate.

[2] Kim Philby, who worked in the building during the war, described it as, "a dingy building, a warren of wooden partitions and frosted glass windows...served by an ancient lift.

[4] During the 1990s, the building was used by the project team for the Jubilee Line Extension to the London Underground.