To replace the increasingly obsolete de Havilland Mosquito as a night fighter, the Meteor was adapted to serve in the role as an interim aircraft. Gloster had initially proposed a night fighter design to meet the Air Ministry specification for the Mosquito replacement, based on the two seater trainer variant of the Meteor, with the pilot in the front seat and the navigator in the rear. Once accepted however, work on the project was swiftly transferred to Armstrong Whitworth to perform both the detailed design process and production of the type; the first prototype flew on 31 May 1950. Although based on the T.7 twin seater, it used the fuselage and tail of the F.8, and the longer wings of the F.3. An extended nose contained the AI Mk 10 (the 1940s Westinghouse SCR-720) Air Intercept radar. As a consequence the 20 mm cannons were moved into the wings, outboard of the engines. A ventral fuel tank and wing mounted drop tanks completed the Armstrong Whitworth Meteor NF.11.

The NF.12 was a longer nosed version of the NF.11 with American AN/APS-21 radar, this was balanced by a slightly larger fin, first flown on 21 April 1953, 100 built by Armstrong Whitworth. All examples were operated by the RAF.