The key part played by Winston Churchill in shaping the course of World War II still excites great interest in historians worldwide. In the course of his research, Robin Denniston has uncovered previously unknown files of diplomatic intercepts which show that Churchill's role in British foreign policy and war planning was far more significant than has hitherto been supposed. This ground-breaking book explores Churchill's use of secret signals intelligence before and during World War II and also sheds fresh light on Britain's relations with Turkey. Robin Denniston discloses a plan to open a second front in the Balkans, from Turkey across the eastern Mediterranean, to hasten D-Day in the west. He also reveals new information on the Cicero spy scandal in 1943 when top secret Foreign Office documents were stolen in Ankara by the British Ambassador's valet, who passed them to the Germans, the biggest Foreign Office security lapse during the war.