The Napier Scorpion was a liquid-fuelled rocket engine; using hydrogen peroxide / kerosene propellant chemistry. The first Scorpion NSc-1 was successfully flight-tested in an Canberra. From 1956 the Double Scorpion NScD-1 was fitted experimentally to two Canberra light bombers, it had better high altitude performance. A world altitude record of 70,300 feet was set by Canberra WK163 on 28 August 1957. The Double Scorpion was also considered for use in the English Electric P.1A interceptor. The project was cancelled in 1959.