The conflict at sea between Allied merchant ships and their escorts and German U-boats, christened the Battle of the Atlantic by Winston Churchill on 6 March 1941, was arguably the decisive campaign of the Second World War. Only the clash of massed German and Soviet armies on the Eastern Front was as influential in its outcome. To survive, Britain needed imports of food, fuel and raw materials from overseas. If Britain had fallen, there would have been no base for the western Allies to launch a strategic air offensive or a land invasion of the European mainland to defeat Germany and Hitler would have been free to concentrate all his resources against the Soviet Union.