manufacture there, and where developed versions continue to this day. 500 Twins, Meteors, Super Meteors and Constellations 1949–1963 In 1949, Royal Enfields version of the now popular selling parallel twins appeared. This 500cc version was the forerunner of a range of Royal Enfield Meteors, 700cc Super Meteors and 700cc Constellations. Offering good performance at modest cost, these sold widely, if somewhat quietly in reputation. The 700cc Royal Enfield Constellation Twin has been described as the first superbike. 250 cc models The 250cc class was important in the UK as it was the largest engine which a 'learner' could ride without passing a test. In the late 1950s and early 1960s, Royal Enfield produced a number of 250 cc machines, including a racer, the 'GP' and a Scrambler, the 'Moto-X', which used a modified Crusader frame, leading link forks and a Villiers Starmaker engine. The Clipper was a base-model tourer with the biggest-seller being the Crusader, a 248 cc pushrod OHV single producing . In 1965, a variant called the Continental GT, with red GRP tank, five-speed gearbox (which was also an option on the Crusader), clip-on handlebars, rearset footrests, swept pipe and hump-backed seat was launched. It sold well with its race-styling including a fly-screen resembling a race number plate which doubled as a front number plate mount. The Avon 'Speedflow' full sports fairing was available as an extra in complementary factory colours of red and white. Other variants were the Olympic and 250 Super 5, notable for use of leading-link front suspension (all the other 250 road models had conventional telescopic forks) and the 250 'Turbo Twin', fitted with the Villiers 247 cc twin cylinder two-stroke engine. The Royal Enfield GP production-volume racer was first raced in the Manx Grand Prix in September, 1964. Developed in conjunction with Royal Enfield Racing Manager Geoff Duke the first public appearance was at Earls Court Show in November, 1964. Using a duplex-tube frame, leading link forks and one-piece tank and seat unit, the 250cc two-stroke single engine was similar to other small capacity race machines offered from rivals Greeves, Cotton, DMW and particularly Villiers, which provided the engines for these marques and many other manufacturers and bike-builders including the 'Starmaker' competition engine used for the Scorpion racer and Sprite scrambler. Royal Enfield Interceptor During the onslaught of the Japanese motorcycle manufacturers in the late sixties and early seventies, the English factories made