During the critical years 1935 to 1939 the most glaring gap in the RAF's armoury was the lack of any long range fighter, any cannon-armed fighter and any fighter capable of effective bomber escort and night fighting. Leslie Frise and engine designer Fedden talked at length of the possibility of creating a single type out of the Blenheim and Beaufort families that could meet all demands, but no official requirement was forthcoming, other than the strange F.11/37 Specification for a fighter with a heavily armed cannon turret. Eventually the two Bristol leaders did the obvious thing: they proposed a new twin-Hercules two-seater carrying enough armament to blast anything in front of it out of the sky. By using the wing, tail, landing gear, systems and jigs of the Beaufort it could be put into production quickly. The Air Ministry was enthusiastic and the first of what was to be an historic war-winning aeroplane took to the air only six months later. A snub-nosed battleship, it was immensley strong, surprisingly manoeuvrable and a great basis for development. Almost its only operational shortcoming was a tendency to swing on takeoff, which later additions of a large dorsal fin and dihedral tailplane did not cure.

Early models barely exceeded 300 mph with low-power Hercules and, in the absence of Griffon engines, 450 were fitted with Merlins, but these were less powerful and accentuated instability. Speed was soon judged less important when the need for night fighters to beat the Blitz became urgent. Equipped with AI Mk IV radar the early deliveries to 25 and 29 Squadrons were a major reason for the Luftwaffe giving up the Blitz on Britain. Eventually the "Beau" served on all fronts, having thimble-nose AI Mk VII in 1942, torpedoes in 1943, rockets in 1944 and a spate of special installations in 1945. A total of 5,564 were built in England and 364 in Australia, the last fighter and torpedo versions serving with Coastal Command, the Far East Air Force and the RAAF until 1960. To the Luftwaffe it was the most feared opponent even 500 miles out into the Atlantic; to the Japanese it was "Whispering Death", so named because of the quietness of the sleeve-valved engines.