 In June 1940, Sykes joined SO1 (later Special Operations Executive), where he was personal assistant to Colonel Cudbert Thornhill.In October 1941, Sykes was sent out to Tehran as Deputy Director of Special Propaganda under diplomatic cover (Second Secretary at the British Legation) in the aftermath of the Anglo-Soviet invasion of Iran, where he remained until November 1942, when he was transferred to Cairo.Out of a job because his department had been wound up, Sykes found time to write a light novel, "High Minded Murder" (1944), something of a "roman à clef", set in wartime Cairo where Graham Greene's sister Elizabeth was living (Sykes mentions Greene in his biography of Waugh).