Mike Lynch, who has died aged 59 in the wreck of his yacht, was sometimes described as “Britain’s Bill Gates”. It was a huge exaggeration, but Lynch could claim two parallels with Gates: he developed world-leading technology (in his case in machine learning or AI) and, unlike so many UK scientists, he learned how to turn it into commercial success.

Such was this success that his company, Autonomy, was valued at $11bn when he sold it to Hewlett-Packard in 2011, but the fall-out from the sale would come to overshadow his technological achievements, and lead to a national debate about the circumstances in which UK citizens may be extradited to the US.

Lynch founded Autonomy with two partners in 1996. Its software enabled a computer to search huge quantities of diverse information, including phone calls, emails and videos, and recognise words. He told the Independent in 1999: “The way our technology works is to look at words and understand the relationships because it has seen a lot of content before. When it sees the word ‘star’ in the context of film, it knows it has nothing to do with the word moon. Because it works from text, it can deal with slang and with different languages.”

Autonomy became a leading company in Cambridge’s Silicon Fen cluster and established a base in San Francisco. “We knew we had to be successful in America. It was a question of ‘Go West young man, go to San Francisco and be ignored.’ They found it hard to believe that anyone from England could have anything powerful.” Lynch found what he called the “cold-hearted schmooze” to secure funding tough.

But Autonomy’s software, enabling computers to identify and match themes and ideas, and sort mammoth amounts of data, was licensed to more than 500 customers, including the US State Department and the BBC. It was listed on Nasdaq in 1998 and on the FTSE 100 in November 2000, although its value of £5.1bn would be halved within a few months in the collapse of the technology boom and accusations of over-promotion. In 2005 it bought a major US rival, Verity, for $500m.

Lynch’s profile rose with it. In 2006 he was appointed OBE for services to enterprise and the following year joined the board of the BBC. In 2011 he became a member of the government’s Council for Science and Technology, and was named the most influential person in UK IT by Computer Weekly. In 2014 he was elected a fellow of the Royal Society.

Though quietly spoken, he had a reputation for toughness, coloured by a liking for James Bond, which led to Autonomy conference rooms being named after Bond villains, and a tank of piranha fish in reception. (Lynch claimed it belonged to one of his business partners.) Challenged about a company culture where people were “a little fanatical”, he replied: “This is not the place for you if you want to work 9 to 5 and don’t love your work.”

Born in Ilford, east London, to Michael, a firefighter, and Dolores, a nurse, and brought up in Chelmsford, Lynch won a scholarship to the independent Bancroft’s school in Woodford Green, before taking a natural sciences degree at Cambridge, where his PhD in artificial neural networks, a form of machine learning, has been widely studied since.

A saxophone player and jazz lover, he set up his first business, Lynett Systems, while still a student, to produce electronic equipment for the music industry. Later he would attribute some loss of hearing to adjusting synthesisers for bands. He quoted his own experience to highlight the difficulties of finding funding for startup businesses in Britain. He finally negotiated a £2,000 loan from one of the managers of Genesis in a Soho bar.

Lynch’s next venture came out of his research. In 1991 he founded Cambridge Neurodynamics, specialising in computer-based fingerprint recognition. Then he established Autonomy.

The pinnacle of his success appeared to come in October 2011 when Autonomy was purchased by Hewlett-Packard for $11bn and Lynch made an estimated $800m. Shortly afterwards he established a new company, Invoke Capital, for investment in tech companies, and he and his wife, Angela Bacares, whom he had married in 2001, invested about £200m in Darktrace, a cybersecurity company.

But just 13 months after the Autonomy sale, HP announced an $8.8bn writedown of the assets “due to serious accounting improprieties, disclosure failures and outright misrepresentations” which it claimed had artificially inflated the company’s value. The authorities investigated, and while the UK Serious Fraud Office found insufficient evidence, in 2018 the US authorities indicted Lynch for fraud. Soon after, Autonomy’s chief financial officer, Sushovan Hussain, was found guilty of fraud and sentenced to five years in prison.

In March 2019 HP followed up with a civil action for fraud in London. Lynch spent days in the witness box as the civil action stretched over nine months. It ended in January 2022 with the judge ruling that HP had substantially succeeded, but that damages would be much less than the $5bn they had claimed.

Meanwhile the US authorities sought Lynch’s extradition on criminal charges of conspiracy and fraud. In spite of representations by senior politicians and accusations that the US authorities were attempting to exercise “extraterritorial jurisdiction”, a district judge ruled in favour of extradition.

An application for judicial review and a further appeal failed, and in May 2023 Lynch was flown to the US to be held under house arrest in San Francisco, with the prospect of a 25-year sentence.

Charged with wire fraud, securities fraud and conspiracy, on 18 March this year Lynch pleaded not guilty, alongside his former vice-president of finance, Stephen Chamberlain. On 6 June, they were found not guilty of all charges. Chamberlain died after being hit by a car on 17 August.

Lynch declared that he wanted to get back to what he loved doing – innovating. But he had little opportunity to do so. He soon embarked on a voyage to celebrate his acquittal, with family, colleagues and business associates. It ended with the sinking of his yacht, Bayesian – named after the 18th-century mathematician, Thomas Bayes, whose work on probability had informed much of his thinking – in a violent storm off the coast of Sicily.

Lynch is survived by his wife and elder daughter, Esme. Their other daughter, Hannah, was also on board the Bayesian.

• Michael Richard Lynch, technology entrepreneur, born 16 June 1965; died 19 August 2024