Collishaw remained with the new Royal Air Force after the war. He saw action in south Russia in 1919, then served in a variety of home and overseas stations in the years before World War II. In 1940, he was in command of 202 Group, the Royal Air Force units in the western desert of Egypt, when war with Italy began on 10 June. Collishaw's theater commander, Air Chief Marshal Sir Arthur Longmore, ordered him to keep his aggressive tendencies in check, largely because of immediate difficulties of supply. But as reinforcements arrived, Collishaw was able to extend air operations against the Italians.
In December 1940, preparations began for a full-scale land offensive into Libya. Collishaw's air units commenced a wide-ranging offensive to set the stage and provided close support for Lieutenant General Sir Richard O'Connor's spectacularly successful advance and destruction of Italian forces under Marshal Rodolfo Graziani. This success was quickly reversed as the British sent troops and aircraft to Greece and German forces under Generalleutnant (U.S. equiv. major general) Erwin Rommel commenced operations in Africa. Collishaw's air forces provided support as the British retreated and then again stabilized their situation on the Egyptian border.
Collishaw returned to Britain on the staff of Headquarters, Fighter Command in August 1941, then took command of 14 Group, Fighter Command on 21 March 1942. He retired as an air vice marshal in 1943 and remained in England until the end of the war, when he returned to Vancouver. In Canada, he set up several very successful mining-exploration operations. Collishaw died in West Vancouver on 28 September 1976.
Paul E. Fontenoy
Collishaw, Raymond. Air Command, a Fighter Pilot's Story. London: W. Kimber, 1973.; Playfair, I. S. O., et al. The Mediterranean and Middle East. Vols. 1–3. London: Her Majesty's Stationery Office, 1954–1960.; Richards, Denis, and Hilary St. G. Saunders. Royal Air Force, 1939–1945. London: Her Majesty's Stationery Office, 1953–1954.