During the Second World War, a group of basement offices in Whitehall served as the centre of Britain’s war effort. The complex, known as the Cabinet War Rooms, was occupied by leading government ministers, military strategists and Prime Minister Winston Churchill.
Following the devastation of the First World War, military planners feared up to 200,000 casualties from bombing in the first week of a future war. Plans to evacuate the prime minister, cabinet and essential staff from London were drawn up as early as the 1920s, but concern that Londoners would feel abandoned if the prime minister and government were in a safe place, and issues about the speed of evacuation, led to a search for an emergency shelter in central London.
In June 1938 the New Public Offices building was selected. It was near Parliament, with a strong steel frame and a large basement.
The basement was adapted to provide meeting places for the War Cabinet during air raids and also housed a military information centre based around a ‘Map Room'. Here, vital information for King George VI, Prime Minister Churchill and the armed forces was collected.
The Cabinet War Rooms became fully operational on 27 August 1939, a week before Britain declared war on Germany.
Churchill’s War Cabinet met here 115 times, most often during the Blitz and the later German V-weapon offensive. The Cabinet War Rooms were in use 24 hours a day until 16 August 1945, when the lights were turned off in the Map Room for the first time in six years.