Deep under Whitehall lies a labyrinth of offices, map rooms and sleeping quarters whose very existence was kept a mortal secret from the Nazis. For this was where Churchill's war cabinet and military chiefs met to plan the strategy that was eventually to bring victory over Hitler in the Second World War. Restored today to exactly the condition they were left in at the end of the war in August 1945, the Cabinet War Rooms are a powerfully evocative time capsule. Military historian Richard Holmes has written a superb book that explains their central role in Britain's finest hour.
It was from here that Winston Churchill delivered some of his most stirring broadcasts and where he took many of the most crucial decisions of the war. During the Blitz of 1940-41, and during the V-weapon assaults on London in 1944-45, Churchill occasionally had to sleep the night here too, although he hated the stuffy atmosphere. His bedroom and office, officially designated Room 65A, have also been preserved exactly as they were, right down to the red metal box in which he extinguished his cigars.
The origins of the Cabinet War Rooms lie in the growing realisation by the war planners of the 1930s that aerial bombardment would play a vital role in any future conflict. The civilian casualties suffered during the Spanish Civil War from the ravages of German and Italian bombers convinced British governments of the necessity of protecting the population of London. If the high command was also to be protected, a bunker deep underground needed to be constructed as soon as possible.
Work began in the summer of 1938 to turn some basement storage rooms far under the Treasury into what was then called the Central War Room, which comprised at first little more than a map room and a meeting area. It was particularly convenient for MPs since it was situated almost halfway between No 10 and the Houses of Parliament. During the Munich crisis of September 1938, the rooms were kept fully staffed in case war broke out, but they did not become fully operational until a week before the war started the following year. What had only really started out as a "temporary" expedient until some custom-built bunker was created elsewhere wound up servicing Britain's senior strategists for the next six years.
On 21 October 1939, the first cabinet meeting took place there, under the then prime minister Neville Chamberlain. No one much liked having to meet underground, especially as no one seems to have stopped smoking when down there, but with the Phoney War likely soon to break out into a full-scale land conflict, everyone recognised the necessity of being prepared for the worst. Soon after Churchill became prime minister in May 1940, he made a special visit and announced: "This is the room from which I'll direct the war."
Churchill started holding his cabinet meetings in the war rooms on 29 July 1940, only a few weeks before the start of the Luftwaffe's Blitz on London. It was the first of 115 war cabinet meetings convened there. The sound of exploding bombs, anti-aircraft fire and falling shrapnel could not be heard during the cabinet's deliberations, but no one knew for certain whether the thick concrete and sandbag defences would survive a direct hit from a German high explosive bomb.
On 26 September 1940, the rooms survived a near-miss when a bomb hit the Clive Steps almost directly above them, which prompted the authorities to construct a huge concrete slab to protect the cabinet room itself. Although at least 140 bombs had fallen on that area of Whitehall by the following February, the rooms escaped serious damage. Betty Green, a secretary working there at the time, reminisced: "I used to spend every other night sleeping in the office ... sometimes I was there for about three nights running because I just couldn't get home, so in some ways I was fortunate that one could get a good night's sleep because you didn't hear the bombs raining down, which is just as well, because we'd have all been buried alive in the Cabinet War Rooms."
During the height of the Blitz, Churchill often held meetings at unusual times of the day and night; sometimes, they would carry on long after midnight (to the private fury of some of his staff who, unlike him, had not had the benefit of an afternoon nap). But unconventional though he was as a war leader, Churchill understood the importance of maintaining morale, and from Room 60 he delivered several BBC broadcasts to the British nation, its empire and commonwealth, the US and occupied Europe.
Holmes vividly recaptures what it was like to work in Churchill's bunker, the fabulous highs and dispiriting lows. One of the tiny chambers off the main corridor is called the transatlantic telephone room. It was once used to store brooms and mops, but in 1943 a direct telephone link was established there connecting the war rooms to the White House. It was down this line that Churchill spoke directly, via a scrambler telephone, to President Roosevelt. The huge "Sigsaly" scrambler device for the connection was housed in the basement of Selfridges. Churchill and Roosevelt implicitly trusted the scrambler, and the sophisticated enciphering radio waves were never cracked by German intelligence. Holmes has written a book that serves both as a guide to the fascinating Cabinet War Rooms and also as a fitting memorial to the men and women who worked so hard down there over six gruelling years of war.
Andrew Roberts's The Storm of War: A New History of the Second World War (Allen Lane) is published in August
