On 4 April 1957 Beamont made the first flight of the P.1B (XA847) exceeding Mach 1 during this flight. On 25 November he reached Mach 2, the first time in a British aircraft. During the early flight trials of the P.1B speeds in excess of 1,000 mph were achieved daily. During this period the Fairey FD2 delta held the world speed record (1,132 mph achieved on 10 March 1956 and held till December 1957). While the P.1B was potentially faster than the FD2, it lacked the fuel capacity to provide one run in each direction at maximum speed to claim the record in accordance with international rules.