Blue Steel is an air-surface missile carrying a thermonuclear warhead and intended to enable the V bombers to operate without going into areas in which they would be exposed to concentrated guided weapon attack. It has a canard configuration with small delta-shaped foreplanes for pitch control, a rear-mounted wing with inboard ailerons and a pair of fins of which the upper carries a yaw damper; the lower fin folds sideways to give sufficient ground clearance when the missile is installed on the aircraft (Fig. 1). Its exact performance cannot yet be stated but it is the largest of the British Missiles to get into Service.