The Boulton Paul Defiant is a British fighter aircraft that was designed and built by the Boulton Paul Aircraft Company in the late 1930s. It was a unique aircraft in that it was designed to be a turret fighter, meaning it had a powered gun turret mounted behind the pilot that could be used to engage enemy aircraft.

The Defiant was initially developed as an interceptor aircraft, intended to engage German bombers at night, but it was later used as a day fighter. It was powered by a Rolls-Royce Merlin engine and armed with four .303 Browning machine guns in the turret, which had a 360-degree firing arc. However, it had no fixed forward-firing guns, which made it vulnerable to attack from the front.

The Defiant saw its first combat action in May 1940 during the Battle of France, but it suffered heavy losses due to its vulnerability to frontal attacks. It was later used in the Battle of Britain, where it was assigned to duties such as convoy escort and air-sea rescue. Despite its limitations, some Defiant crews achieved notable successes, such as shooting down German fighters, including Messerschmitt Bf 109s.

As the war progressed, the Defiant was gradually replaced by more advanced fighters such as the Spitfire and Hurricane, and it was eventually withdrawn from service in 1942. However, the Defiant’s turret technology was used in other aircraft designs, such as the American B-17 Flying Fortress bomber. A few examples of the Defiant can still be seen in museums today.