The Hawker Siddeley (later British Aerospace) Red Top was the third indigenous British air-to-air missile to enter service, following the de Havilland Firestreak and limited-service Fireflash. Originally a modified version of the Firestreak, Red Top emerged as a much more capable weapon, with roughly double the range, a more sensitive seeker giving limited all-aspect capability, and an even larger warhead than the already-large one in Firestreak.