MI9, the British Directorate of Military Intelligence Section 9, was a department of the War Office between 1939 and 1945. During World War II it was tasked with aiding resistance fighters in enemy occupied territory and recovering Allied troops who found themselves behind enemy lines (for example, aircrew who had been shot down and soldiers stranded after the Battle of Dunkirk). It also communicated with British prisoners of war and sent them advice and equipment.