Sir Clive Sinclair obituary

Inventor who brought pocket calculators and the earliest accessible computers into British homes

Sir Clive Sinclair, who has died aged 81 from cancer, was the inventor who brought pocket calculators and the earliest cheap and accessible miniature computers into British homes in the 1980s.

For a few years he seemed to be the epitome of the new hi-tech, go-ahead Britain the Tory government was striving to promote. He was made businessman of the year, knighted, championed by Margaret Thatcher and became, briefly, a multimillionaire. But, proving a better inventor and self-publicist than an entrepreneur, his reputation came a cropper in 1985 with the invention of the C5, his prototype electric car.

The three-wheeled, low-slung, lightweight, open, plastic-sided vehicle, retailing for £399, whose top speed was 15mph and whose battery needed recharging every 20 miles, was rushed into production, with Sinclair predicting annual sales of 100,000. But its flaws were only too evident and it sank under gales of derisive media laughter. Journalists had been led to expect a full-sized vehicle from the genius inventor, not a tricycle with a modified Hoover washing machine engine.

ZX80 home computer.
Sinclair’s ZX80 home computer. Photograph: Alamy

Marketed with the slogan “A Whole New Way to Get About”, it was damned with faint praise by the Department for Transport, which said: “As an alternative to pedal cycles it is not thought likely to have a worse safety record.” But drivers felt vulnerable, not only to passing traffic but to heavy breezes and gusts of rain, and only a few thousand were ever sold. Within months Sinclair was forced to sell his computer company to Alan Sugar, the owner of Amstrad, close the office headquarters in Cambridge and lay off virtually all the staff.

Many years later, Sinclair admitted that January had not been the best time to have launched the C5, as its batteries tended to pack up in cold weather. “It was a good idea then and now,” he told the Independent on Sunday in 2010. “We sold quite a few thousand and people loved them, but clearly I should have handled it differently. It could have succeeded. I rushed at it too much.”

Sinclair was the son and grandson of engineers, the eldest of three children of George Sinclair, a mechanical engineer who had his own machine tool business for a time, and Thora (nee Marles). Born in Richmond, Surrey, early in the second world war, he had his childhood disrupted, first by evacuation to Devon with his mother and later, after the collapse of his father’s business, by moves to different parts of the south of England, where he was educated at a succession of private schools. His enthusiasm for inventions started early – apparently because of an inventor character on the children’s radio programme Toytown – and by the age of 12 he had designed a one-person submarine out of a petrol tank.

Leaving St George’s college in Weybridge with two A-levels, in maths and physics, he decided not to go to university. Instead he found a job, initially on the trade paper Practical Wireless, before going on to edit electronics handbooks and becoming technical editor on the journal Instrument Practice.

Clive Sinclair demonstrating the C5 with snow on the ground
Sinclair demonstrating the C5, his prototype electric car, in 1985. He later admitted January was probably not the best time to launch it. Photograph: PA

Sinclair’s passion was for miniaturisation. In 1962 he and his first wife, Ann (nee Trevor Briscoe), set up a company in their flat in Pimlico, central London, making micro amplifiers and then cheap pocket radios marketed as the Sinclair Slimline, which they assembled using transistors bought cheaply from Plessey and dispatched to customers from their kitchen table.

The first Sinclair pocket calculators appeared 10 years later, powered by a microchip and half the size and price of the bulkier models then on the market. Although the calculators’ design and reliability left much to be desired, they retailed for just under £80 but cost only £10 to make, and orders flooded in at the rate of 100,000 a month.

A digital plastic watch followed, but this, too, had problems, including a short battery life and faulty casing. Sinclair’s next project was to design a slimline television and a pocket television, both well ahead of their time, but his company was in growing financial difficulties as its calculator business was undercut by larger, better-financed, rivals. Sinclair Radionics required bailing out in 1976 by the National Enterprise Board and again the following year.

Eventually the board acquired a three-quarters share of the business and Sinclair left in 1979 to set up a new company, Sinclair Research, which would eventually produce the first cheap personal computers that could be used at home. This was at a time when most people thought of computers as whirring machines as large as a room. Sinclair’s first, the ZX80, was 9in (23cm) wide and 7in (18cm) deep and could be bought in kit form for £79.95 or £20 more as ready assembled – a fifth of the price of other basic computers in offices. It turned out that he was answering a need people did not know they had for their leisure time.

Sinclair had achieved his ambition of producing a computer for less than £100 but it was very basic, needing to be plugged into the television to provide a screen and with a cassette to store data. A year later came the ZX81 and then, marginally more sophisticated, and costing £125, the ZX Spectrum, which was made under licence in the US by Timex.

With no commercial rivals initially, the machines sold in their thousands – a quarter of a million of the 1981 model in the first year – and the company’s profits soared. By 1982 it was making £8.55m on a turnover of £27m; a year later the company was valued at £136m and the profits had reached nearly £20m. If many owners and their children used their computers to play new sorts of games such as Monster Maze, they were also taught about programming and other technological skills.

Clive Sinclair launching his A-bike
Sinclair launching his A-bike in 2006. Photograph: Adrian Dennis/AFP/Getty Images

Then came the C5 fiasco. Sinclair was suddenly transformed from bearded boffin wizard to a figure of fun, a cross between Einstein and Willy Wonka in the later words of the actor Alexander Armstrong, who played him in the 2009 TV drama Micro Men. The same year the Guardian described him as one part visionary, one part dotty uncle and one part marketing genius.

“If an idea is good enough it’s going to appear pretty crazy to almost everybody,” he explained to the Independent on Sunday. “Either you do it yourself or it ain’t going to happen. I never feel, my God, that’s the end of the world, I just get on with the next stage. I am not a businessman by nature … I certainly have no desire to be hugely rich; I mean, I have been, but that was just something that happened.”

The ridicule did not stop Sinclair continuing to pursue inventions, even as his company reduced in size to just himself. In coming years there would be an electric bicycle called a Zike and a bike battery engine called a Zeta, a tiny radio that could fit in the ear, and an A-bike that commuters could fold up and carry into their offices. His daughter, Belinda, said he was still at work on ideas last week. Strangely, he did not himself use a computer, email, or the internet, and preferred a slide rule to the calculator he had developed.

There were other interests: Sinclair claimed an IQ of 159 and was chair of the British arm of Mensa for many years, and he was a keen poker player, enjoyed poetry and ran marathons.

He and Ann divorced in 1985. In 2010 he married Angie Bowness, a former Miss England beauty queen and pole dancer, 34 years his junior, whom he had met at Stringfellows nightclub in 1996; they divorced in 2017.

Sinclair is survived by his three children, Bartholomew, Belinda and Crispin, from his first marriage, five grandchildren and two great-grandchildren.

• Clive Marles Sinclair, inventor, born 30 July 1940; died 16 September 2021

Contributor

Stephen Bates

The GuardianTramp

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