Boulton Paul Defiant

The Boulton Paul Defiant was a British interceptor aircraft that served with the Royal Air Force (RAF) during the Second World War. The Defiant was designed and built by Boulton Paul Aircraft as a "turret fighter", without any forward-firing guns. It was a contemporary of the Royal Navy's Blackburn Roc. The concept of a turret fighter related directly to the successful First World War-era Bristol F.2 Fighter.

In practice, the Defiant was found to be reasonably effective as a bomber–destroyer, but vulnerable to the Luftwaffe's more agile, single-seat Messerschmitt Bf 109 fighters. Lack of forward armament proved to be a major weakness in daylight combat and its potential was only realized when it switched to night combat. It was supplanted in the night fighter role by the Bristol Beaufighter and de Havilland Mosquito. The Defiant found use in gunnery training, target towing, electronic countermeasures (ECM) and air-sea rescue. Among RAF pilots it had the nickname "Daffy".

Boulton Paul Defiant
Class Aircraft
Type Fighter
Manufacturer Boulton & Paul Ltd
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1937
Country Name Operational Year Retirement Year
Australia View
Canada View
Poland View
United Kingdom - UK (Great Britain) 1939 View
United States of America View
ManufacturerName Production From Production To Quantity
Boulton & Paul Ltd 1064 View


  • Defiant Mk I : Two-seat turret fighter for the RAF, powered by a 1,030 hp (768 kW) Rolls-Royce Merlin III piston engine; 723 built.
  • Defiant NF Mk I Defiant Mk I converted into night fighters
  • Defiant NF Mk IA NF Mk I with Airborne Interception radar.
  • Defiant ASR Mk IMk I carrying air-dropped dinghies for air-sea rescue.
  • Defiant TT Mk IDefiant Mk IIs converted to target tugs; 150 conversions.
  • Defiant Mk IITwo-seat night fighter for the RAF, powered by a 1,280 hp (954 kW) Rolls-Royce Merlin XX piston engine, and fitted with the AI Mk IV airborne interception radar; 210 built.
  • Defiant TT Mk IIIDedicated turret-less target tug; 140 built from new.

In October 1939, No. 264 (Madras Presidency) Squadron was reformed at RAF Sutton Bridge to operate the Defiant. Initial training and development of tactics began with other aircraft as it received its first Defiants only in early December at Martlesham Heath. They began night fighter training in February 1940. The squadron tested its tactics against British medium bombers – Hampdens and Blenheims – and 264's CO flew against Robert Stanford Tuck in a Spitfire, showing that the Defiant could defend itself by circling and keeping its speed up. By March, 264 Squadron had two flights operational with Defiants and No. 141 Squadron received its first Defiant. When the Defiant was first introduced to the public, the RAF put out a disinformation campaign, stating that the Defiant had 21 guns: four in the turret, fourteen in the wings and three cannon in the nose.

The first operational sortie came on 12 May 1940. Defiants flew with six Spitfires of 66 Sqn, and a Ju 88 was shot down over the Netherlands. The following day, in a patrol that was a repetition of the first, Defiants claimed four Ju 87s, but were subsequently attacked by Bf 109Es. The escorting Spitfires were unable to prevent five of the six Defiants being shot down by a frontal attack.

During the evacuation of the British Expeditionary Force from Dunkirk, the squadron was forward-based at RAF Manston, as one of the 16 squadrons that No. 11 Group had available to cover the evacuation. On the 27th 264 Sqn claimed three He 111 and two damaged. On the 28th, shortly after takeoff, ten Defiants were attacked by about 30 Bf 109s – forming a circle, they claimed six German fighters for the loss of three Defiants.

The Defiant was initially successful against enemy aircraft. Its best day was 29 May 1940, when No. 264 Sqn claimed 37 kills in two sorties: 19 Junkers Ju 87 Stuka dive bombers, mostly picked off as they came out of their dives, nine Messerschmitt Bf 110 twin-engined heavy fighters, eight Bf 109s, and a Ju-88. One Defiant gunner was lost after he bailed out, although the aircraft made it back to its base to be repaired.

Role Two-seat fighter, night fighter,trainer, target tug
Manufacturer Boulton Paul Aircraft
Designer John Dudley North
First flight 11 August 1937
Introduction December 1939
Status Retired
Primary users Royal Air Force
Royal Australian Air Force
Royal Canadian Air Force
Polish Air Force
Number built 1064

General characteristics

  • Crew: two: pilot, gunner
  • Length: 35 ft 4 in (10.77 m)
  • Wingspan: 39 ft 4 in (11.99 m)
  • Height: 11 ft 4 in (3.46 m)
  • Wing area: 250 ft² (23.2 m²)
  • Empty weight: 6,078 lb (2,763 kg)
  • Loaded weight: 8,318 lb (3,781 kg)
  • Max. takeoff weight: 8,600 lb (3,909 kg)
  • Powerplant: 1 × Rolls-Royce Merlin III liquid-cooled V12 engine, 1,030 hp (768 kW)


  • Maximum speed: 304 mph (264 knots, 489 km/h) at 17,000 ft (5,180 m)
  • Cruise speed: 175 mph (152 knots, 282 km/h) at 15,000 ft (4,570 m)
  • Range: 465 mi (404 nmi, 749 km)
  • Endurance: 1.78 hr
  • Service ceiling: 31,000 ft[35] (9,250 m)
  • Wing loading: 33.27 lb/ft²[9] (163.0 kg/m²)
  • Power/mass: 0.124 hp/lb (204 W/kg)
  • Climb to 15,000 ft (4,600 m): 8.5 min


  • Guns: 4 × 0.303 in (7.7 mm) Browning machine guns in hydraulically powered dorsal turret (600 rpg)

End notes