Leconfield House - former MI5 headquarters

Leconfield House became the headquarters for MI5 (Military Intelligence 5, responsible for domestic security and counter-intelligence in the UK) just after the end of the Second World War. During the war, MI5 had occupied Bleneim Palace in Oxfordshire, on loan from the 10th Duke of Marlborough, John Albert William Spencer-Churchill (1897-1972).

Leconfield House is a commercial building today. When MI5 occupied it in 1945, Leconfield House had the distinction of having gun ports in its south-west corner, aimed up Curzon Street towards Hyde Park Corner, apparently ready for a wartime invasion by the German Army.

Although popularly accused (by the Soviets and Communists, of course) of keeping these ports operational, Nigel West's book A Matter of Trust: MI5 1945-1972 confirmed that the ports were all bricked off after the war and the area behind them housed teletype printers, not machine guns and cannons.