A cantilever low-wing monoplane of all-metal construction, the Defiant had a Boulton Paul power-operated turret containing four 7.62mm Browning machine-guns.
The prototype flew for the first time on 11 August 1937, entered service in December 1939 and was used operationally by No 264 Squadron for the first time on 12 May 1940. Defiants were an immediate success; unsuspecting enemy aircraft making a conventional attack from the rear were subjected to the concentrated fire power of the four Brownings. Within 19 days Defiants were credited with the destruction of 65 aircraft - 38 on one glorious day. Unfortunately for the British, the Luftwaffe pilots were quick to realise there were certain sectors at which the battery of machine-guns could not be directed. Thereafter they were subjected to attack from below or head-on, against which they had no defence, and they were quickly taken out of front-line daylight service. There was a further brief spell of success in the night fighter role, during the winter of 1940-41, after which Defiants were used largely for target-towing, air/sea rescue, army cooperation and gunnery training.
