His first home computer, the ZX80, named after the year it appeared, revolutionised the market, although it was a far cry from today’s models. At £79.95 in kit form and £99.95 assembled, it was about one-fifth of the price of other home computers at the time. It sold 50,000, units while its successor, the ZX81, which replaced it, cost £69.95 and sold 250,000. Many games industry veterans got their start typing programs into its touch-based keyboard and became hooked on games such as as 3D Monster Maze and Mazogs. The ZX80 and ZX81 made him very rich: in 2010 Sinclair told the Guardian: “Within two or three years, we made £14m profit in a year.”
In 1982, he released the ZX Spectrum 48K. Its rubber keys, strange clashing visuals and tinny sound did not prevent it being pivotal in the development of the British games industry.
But it flopped, and Sinclair Vehicles found itself in receivership by October of the same year. Reviews expressed concerns about the safety of driving a vehicle below the sight line of other motorists, as well as exposure to the elements. The following year, Sinclair sold his computer business to Amstrad.