Development started in 1944, with the goal to create a capable replacement for the de Havilland Mosquito. W. E. W. Petter, chief designer of English Electric, proposed an aircraft powered by two Rolls Royce Avon turbojets, located in straight wings of large area. The first flight took place on 13th May 1949, with te st pilot Ronald Beamont demonstrating the type's fighter like agility, which was due to the low wing loading. The aircraft entered operational status as the B.Mk 2 in 1951.