On November 25, 1958 the English Electric P.1B, XA847, became the first British aircraft to fly at Mach 2. The pilot, ex BAC chief test pilot Roland Beamont recalled, in the January 1983 issue of Aeroplane Monthly, this and earlier flights carried out by him during the Lightning’s development
From the earliest days in the P.1 development programme in the 1950s, the design team at English Electric’s Warton base had been fully aware of the aircraft’s potential speed. The team knew that the 60° wing sweep of the basic P.1 configuration could lead to performance far in excess of the Mach 1.2 design speed of the prototype when inevitably more thrust became available. So all aspects of the design, including the shoulder wing, low tailplane aerodynamics and the irreversible power controls on three axes — the first in this configuration to fly in the United Kingdom — were developed with performance stretch very much in mind.