.
The
Cabinet War Rooms (now an historic underground complex) housed a
British government command centre throughout WW2, being abandoned in August 1945 after the surrender of Japan.
As above, in
1936 the
Air Ministry, the British government department responsible for the
Royal Air Force, believed that in the event of war enemy aerial bombing of London would cause up to 200,000 casualties per week.
British government commissions under
Warren Fisher and
Sir James Rae in
1937 and
1938 considered that key government offices should be
dispersed from central London to the suburbs, and
non-essential offices to the
Midlands or
North West. Pending this dispersal, in
May 1938 Sir Hastings Ismay, then
Deputy Secretary of the
Committee of Imperial Defence, ordered an
Office of Works survey of Whitehall to identify a suitable site for a temporary emergency government centre. The Office concluded the most suitable site was the basement of the New Public Offices (NPO), a government building located on the corner of
Horse Guards Road and Great George Street, near
Parliament Square. The building now accommodates
HM Treasury.
Work to convert the basement of the New Public Offices began, under the supervision of Ismay and Sir Leslie Hollis, in
June 1938. The work included installing communications and broadcasting equipment, sound-proofing, ventilation and reinforcement. Meanwhile, by the summer of 1938 the War Office, Admiralty and Air Ministry had developed the concept of a Central War Room that would facilitate discussion and decision-making between the Chiefs of Staff of the armed forces.
Construction of the Cabinet War Rooms, located beneath the
Treasury building in the
Whitehall area of
Westminster, began in
1938. They became fully operational on
27 August 1939, a week before
Britain declared war on Germany. The War Rooms remained in operation throughout the Second World War, before being abandoned in August 1945 after the
surrender of Japan.
As ultimate authority lay with the civilian government the Cabinet, or a smaller
War Cabinet, would require close access to senior military figures. This implied accommodation close to the armed forces' Central War Room. In
May 1939 it was decided that the Cabinet would be housed within the
Central War Room. In
August 1939, with war imminent and protected government facilities in the suburbs not yet ready, the
War Rooms became operational on 27 August 1939, only days before the
invasion of Poland on 1 September, and Britain's declaration of war on Germany on 3 September.
During its operational life
two of the Cabinet War Rooms were of
particular importance. Once operational, the
facility's Map Room was in constant use and manned around the clock by officers of the Royal Navy, British army and Royal Air Force. These officers were responsible for producing a daily intelligence summary for the King, Prime Minister and the military Chiefs of Staff.
The other key room was the
Cabinet Room. Until the opening of the
Battle of France, which began on
10 May 1940, Prime Minister
Neville Chamberlain's war cabinet met at the War Rooms only once, in October 1939. Following
Winston Churchill's appointment as Prime Minister, Churchill visited the Cabinet Room in
May 1940 and declared: 'This is the room from which I will direct the war'. In total 115 Cabinet meetings were held at the Cabinet War Rooms, the last on 28 March 1945, when the German
V-weapon bombing campaign came to an end.
On 22 October 1940, during
the Blitz bombing campaign against Britain, it was decided to increase the protection of the Cabinet War Rooms by the installation of a massive layer of concrete known as 'the Slab'. Up to 5 feet (1.5 metres) thick, the Slab was progressively extended and by spring 1941 the increased protection had enabled the Cabinet War Rooms to expand to three times their original size. While the usage of many of the War Rooms' individual rooms changed over the course of the war, the facility included dormitories for staff, private bedrooms for military officers and senior ministers, and rooms for typists or
telephone switchboard operators.
Two other notable rooms include the
Transatlantic Telephone Room and
Churchill's office-bedroom. From 1943, a
SIGSALY code-scrambling encrypted telephone was installed in the basement of
Selfridges, Oxford Street connected to a similar terminal in the
Pentagon building. This enabled Churchill to speak securely with American
President Roosevelt in Washington, with the first conference taking place on
15 July 1943.
Later extensions were installed to both 10 Downing Street and the specially constructed Transatlantic Telephone Room within the Cabinet War Rooms. Churchill's office-bedroom included
BBC broadcasting equipment; Churchill made four wartime broadcasts from the Cabinet War Rooms. Although the office room was also fitted out as a bedroom, Churchill rarely slept underground, preferring to sleep at
10 Downing Street or the No.10 Annexe, a flat in the New Public Offices directly above the Cabinet War Rooms. His daughter
Mary Soames often slept in the bedroom allocated to Mrs Churchill.
