No. 141 Squadron of the Royal Air Force was formed on 1 January 1918 at Rochford, for home defence in the London Area. The Squadron moved to RAF Biggin Hill in February and giving up its mixed collection of types in favour of Bristol F.2 Fighters during March. In March 1919, it moved to Ireland, and was disbanded the following year, on 1 February 1920. 141 Sqn was reformed on 4 October 1939 at RAF Turnhouse and was first equipped with Gloster Gladiators then Bristol Blenheims. These were replaced with the Boulton Paul Defiants in April 1940.