Clive Sinclair, Inventive Computer Pioneer, Dies at 81

With personal computers, Mr. Sinclair applied his creativity to technologies that were becoming ripe for commercialization, like electronics, semiconductors and software. The same could not be said for his next ambitious venture: electric vehicles.

Mr. Sinclair was convinced that electric cars were the future of transportation, but he was way ahead of the technology and economics that would one day make them possible. In 1985, he introduced the C5, a vehicle that was aptly described as a souped-up golf cart. Selling for 399 pounds, or about $450, it had a top speed of 15 miles an hour, a range of 20 miles and pedals to assist on hills. Mr. Sinclair described it as a steppingstone toward a full-scale electric car. “The C5 is the first of a family of electric vehicles,” he said.

He had hoped to sell 100,000 of his electric vehicles in 1985. But only about 4,500 were sold, and the business was shut down by the end of the year after he had sunk a lot of his own money into the venture. With Sinclair computer sales beginning to tail off, and short of funds, Mr. Sinclair sold the computer business in 1986 to Amstrad, another British personal computer maker.

Mr. Sinclair endeared himself to the British public partly because he embodied a classic English type — the eccentric inventor, or “boffin,” a complimentary term. His interests and tastes were wide-ranging. He collected modern art, but he was also a lover of classical music and poetry, particularly that of William Butler Yeats, Gerard Manley Hopkins and Robert Frost.

His days, described in The Times Magazine article in 1985, typically began with a six- or seven-mile run through Hyde Park in London at 6:30 a.m. (He completed several New York marathons.) “I sort the day out by running,” he said. “I might think about a business problem or a lecture, but I might also think about women, weather or poetry.”

In addition to his daughter, he is survived by his sons, Crispin and Bartholomew; five grandchildren; and two great-grandchildren. His two marriages ended in divorce.

Mr. Sinclair was tinkering with inventions until shortly before he died, Ms. Sinclair said, “because that was what he loved doing.”