From December 1939, he was a Secret Intelligence Service (SIS) / MI-6 D Section (sabotage) officer sent to Budapest to establish a news service as cover. In April 1941, with the Nazi invasion, he fled to Belgrade, Yugoslavia. In May, he was captured by Italian forces and was later released as part of a prisoner exchange. From late 1942 to mid-1943, he was chief of the Special Operations Executive (SOE) Yugoslav Section in Cairo, Egypt, where he was James Klugmann's supervisor. From January 1945 he was liaison officer with partisans in Liguria, Italy (No. 1 Special Force, Central Mediterranean Forces).