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Eccentric inventor Sinclair went from pocket calculator pioneer to revolutionising home computing


Electric dreams: Sinclair on his much-ridiculed C5 e-tricycle. ‘A plastic version of the Reliant Robin without the roof’ was one description. Photo: PA

Electric dreams: Sinclair on his much-ridiculed C5 e-tricycle. ‘A plastic version of the Reliant Robin without the roof’ was one description. Photo: PA

Electric dreams: Sinclair on his much-ridiculed C5 e-tricycle. ‘A plastic version of the Reliant Robin without the roof’ was one description. Photo: PA

Clive Sinclair, the British inventor, who has died aged 81, achieved major early advances in personal computing but will also be remembered for the spectacular failure of his one-person electric vehicle, the C5.

He had been fascinated by the possibilities of microelectronics and industrial design since his boyhood, and his first career milestone, in 1972, was the slimline Sinclair Executive calculator. Just 9mm thick, this was the first truly pocket-sized gadget of its kind; it sold for £80 (the equivalent of £900 or €1,054) today), but that was half the price of clunkier competitors.

After a brief diversion into digital wristwatches, Sinclair’s next and most significant launch was the ZX80 home computer, brought to market in 1980.

This was the first computer sold in the UK for less than £100. It was succeeded by the slightly more sophisticated ZX81 and then, in 1982, by the ZX Spectrum, by some distance the UK’s bestselling personal computer and for a time a world leader in a rapidly evolving marketplace.

Its memory was minuscule by today’s standards, at a maximum of 48 kilobytes, and the design was not without eccentricities – the cheap rubber keyboard was said to have the feel of “dead flesh”. But the Spectrum heralded a new age of home computing and video gaming.

By 1983 he was a wealthy man and was riding high in public esteem. But the launch of the C5 vehicle in January 1985 turned into a disaster of comic proportions, from which his reputation and corporate fortunes never quite recovered.

“A plastic version of the Reliant Robin without the roof,” was one description of the wobbly, open-topped three-wheeler. It boasted a top speed of 15mph (24kmh) and packed insufficient power to climb the most modest hill, while the low, recumbent position of the driver felt distinctly unsafe in the vicinity of lorries, buses or aggressive cab drivers.

The C5’s range was a theoretical 20 miles (32km), but its batteries drained rapidly in normal conditions and “virtually packed up”, Sinclair had to admit, in frosty temperatures such as those of the launch event at London.

Some 14,000 were manufactured but only 5,000 had been sold before Sinclair Vehicles went into receivership in August 1985.

Clive Marles Sinclair was born in Richmond, Surrey, on July 30, 1940, the son and grandson of engineers. His father ran a machine tools business, but had financial difficulties that disrupted Clive’s education,.

But he had sketched a blueprint for a one-man submarine at the age of 12, and then started selling radio kits by mail order. He chose not to go to university, instead becoming a writer for Practical Wireless magazine and the author of handbooks such as Modern Transistor Circuits for Beginners.

He founded his first company, Sinclair Radionics, in 1961. Products included the Micromatic transistor radio, “smaller than a matchbox”, which Sinclair had begun to design at school, and the Microvision pocket television.

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The aftermath of the C5 debacle coincided with a fall-off in Spectrum sales and the lacklustre launch of the QL (“quantum leap”) personal computing for business users. Running low on cash, Sinclair considered a deal with media mogul Robert Maxwell which did not proceed.

Instead, in 1986, he sold his product range and brand name to Alan Sugar’s Amstrad Corporation for £5m, retaining only a small R&D operation for his own future projects. Amstrad made back the purchase price simply by selling off surplus Sinclair stock – but later attempts to enhance Sinclair products with additional entertainment features proved unsuccessful, and the brand was effectively abandoned in 1992.

Much of Clive Sinclair’s imaginative focus in the 1990s and 2000s was on personal transport. He came up with the Zike electric bicycle; the Zeta electric motor to fit on to conventional bicycles and a similar motor for wheelchairs; the Sea-doo SeaScooter for scuba divers; and finally, in 2008, the A Bike, a lightweight folding cycle with tiny wheels, designed to be carried easily on trains by commuters.

The X-1, a power-assisted pedal-bike reminiscent of the C5, was latterly in the offing. But renewed mass-market success eluded him.

As for the C5 itself, Sinclair was rueful about the mockery it brought, but philosophical about his mistakes: “I think it was a good idea then and I do now. Clearly I should have handled it differently. I rushed at it too much.”

He continued to work, rather secretively, on designs for a variety of advanced electric vehicles, and declared his enthusiasm for the concept of a “flying car”.

He was the long-serving chairman and president of British Mensa, the organisation for people with unusually high IQs (his own was measured at 159). But he was also a high-stakes poker player, appearing in Channel 4’s Late Night Poker and its spin-off, Celebrity Poker Club.

Sinclair married first in 1962 and had two sons and a daughter with Anne Briscoe.

They divorced in 1985

and he later met Angie Bowness, a lap dancer and former Miss England 36 years his junior, who once told a reporter: “I get cross when he’s described as ‘balding Clive’. He’s actually incredibly attractive to women.” They married but later divorced.

(© Telegraph Media Group Ltd 2021)

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