In Europe

their ship, not realising that their find would change the course of the war. Within a week after the ship arrived home the British had access to all kinds of information concerning the German submarine fleet: its targets, its location, even its fuel supplies.
    This gave the British an enormous head start. Thanks to Operation Enigma they knew, for example, all about the German decision to cancelthe planned invasion of England, about the airborne landings on Crete, about the German scenarios for the Soviet Union (and their failure) and about Germany's plans for Italy and Greece. In this way, the Allies were better able to concentrate on the real dangers, and could reserve fewer troops for ‘just in case’.
    One of the most bizarre spots in the Cabinet War Rooms is the little alcove behind a toilet door. This was not Churchill's personal WC, but the terminus of the top secret telephone line with which Churchill and President Roosevelt could – with the aid of incredibly advanced scramblers and more than seventy radio frequencies – consult directly. Here, from this cubicle that everyone thought was Churchill's private loo, the world was governed between 1943–5.
    There was no element of the war into which Churchill put more energy than his relationship with Roosevelt, and with the United States in general. The need was mutual. In early 1941 Roosevelt had sent his friend and close advisor Harry Hopkins to England, to find out what kind of man this whisky-drinking, cigar-smoking British prime minister really was. It was an auspicious move: real fondness arose right away between the two men, a friendship that expanded to include the personal relationship between Churchill and the American president. ‘I am most grateful to you for sending so remarkable an envoy who enjoys so high a measure of your intimacy and confidence,’ Churchill wrote to Roosevelt. Hopkins was deeply impressed by Churchill's statesmanship, and the composure with which the British underwent the constant bombardments. Churchill, he wrote to Roosevelt, was not only the prime minister but ‘the guiding force behind the strategy and course of the war in all essential points. He has an amazing grip on the British people, of all ranks and classes.’
    Hopkins remained in Great Britain for more than a month, twice as long as originally planned. He and Churchill spent a great deal of time together, stayed up all night on several occasions, talking and listening to the new American dance records Hopkins had brought with him. Churchill sometimes stood up and shuffled along to the music. ‘It was a turning point in Anglo-American relations,’ wrote Jean Monnet, who knew both men well. ‘The two countries’ destinies were now linked at the highest level of responsibility.’ Just before he left, at a dinner inGlasgow, Hopkins cited a verse from the Bible: ‘Whither thou goest I will go, and where though lodgest I will lodge; thy people shall be my people, and thy God my God.’ And he added calmly: ‘Even to the end.’ Churchill was in tears.
    Despite these personal ties, however, major differences remained between the British and the Americans. Churchill, in that grand, compelling way so characteristic of him, dreamed of a future union of all English-speaking democracies, unstoppable, victorious and majestic ‘as the Mississippi’. Most Americans, however, were not particularly keen to come to Europe's rescue again. Until late 1941, the mood in Congress was downright isolationist. In September 1940, sixty-seven per cent of the American people believed the country was headed for war, but eighty-three per cent of them were actually against it. President Roosevelt had to manoeuvre very carefully, therefore, not to put at risk his re-election in November 1940.
    The British had come out of the First World War impoverished, and could not in fact afford a long war at all. That, in part, was the background to the policy of appeasement. Chamberlain and his people feared that a second war would mean the financial ruin of the British Empire, and that fear proved justified. Roosevelt saved the situation with the Lend-Lease system, whereby American military goods could be bought on instalment. As Roosevelt put it: when your neighbour's house is on fire you don't haggle first over the price of your fire hose, you lend it to him, and later you may discuss the costs. After 1945, that discussion was explicitly carried on.
    The relations between the two allies