The prototype B.2, serial number WJ954 first flew on 4 September 1953. Finished in a gloss black night operations paint scheme, it became known as the "Black Bomber". Its performance at low level was superior to that of the B.1 (or any other V-bomber), particularly at sea level, with the aircraft being cleared for at low level (with speeds of up to being reached in testing). This was compared to the B.1's sea-level limit of . The Air Ministry ordered 17 production B.2s, which were to be powered by Rolls-Royce Conway turbofans. Although the Valiant B.2's low-level capabilities were significant, the programme was abandoned bacause it was considered that the World War 2 "Pathfinder concept" was obsolete in the nuclear era. The B.2 prototype was used for tests for a few years, including testing use of rockets to boost takeoff, contributing to improvements for the Valiant B.1, before being scrapped in 1958.