Before World War II
Starting in April 1937 and by early 1939 there were five RAF bomber squadrons equipped with the Harrow Mk IIs. By September 1939 these had been replaced by Wellingtons.
Starting in 1940 the Harrow began to be used as a transport. Was often used between Britain and Gibraltar.
Harrows were used in Operation Mutton where they towed aerial mines (Pandoras) in front of German bombers at night. They were guided by ground controllers. In 1941 there were six German bombers destroyed by the Pandoras.
In September 1944 the Harrow was used as an ambulance in Europe.
Last of Line
By late 1944 there were only twelve Harrows remaining in service. Of these, seven were destroyed in Operation Bodenplatte at the Brussels-Evere airfield on New Years Day.
By May 1945 the last five were removed from the RAF.