Clive Sinclair 1985 owing to Sinclair's financial troubles.) The following year, he received a knighthood and formed Sinclair Vehicles Ltd. to develop electric vehicles, which resulted in the unsuccessful Sinclair C5 in 1985. In 1984, Sinclair launched the Sinclair QL computer, intended for professional users. Development of the ZX Spectrum continued with the enhanced ZX Spectrum 128 in 1985. In April 1986, Sinclair Research sold the Sinclair trademark and computer business to Amstrad for £5 million. Sinclair Research Ltd. was reduced to an R&D business and holding company, with shareholdings in several spin-off companies, formed to exploit technologies developed by the company.
Clive Sinclair left school at the age of 18 and instead he sold miniature electronic kits by mail order to the hobby market. Sinclair's Micro Kit was formalised in an exercise book dated 19 June 1958 three weeks before his A-levels. Sinclair drew a radio circuit, Model Mark I, with a components list: cost per set 9/11 (49½p), plus coloured wire and solder, nuts and bolts, plus celluloid chassis (drilled) for nine shillings (45p). Also in the book are advertisement rates for "Radio Constructor" (9d (3¾p)/word, minimum 6/- (30p)) and "Practical Wireless" (5/6 (27½p) per line or part line). Sinclair estimated producing