The British tech tycoon Mike Lynch has said he thought he would die in a US jail if he had not been cleared of allegedly defrauding Hewlett-Packard over a multibillion-dollar business deal.

In his first interview since his acquittal last month on charges related to the $11.1bn (£8.6bn) purchase of his company Autonomy in 2011, the man once lauded as the UK’s answer to Bill Gates said that his lung condition meant he doubted he would have survived a prison term.

He had been accused of duping the US technology company into overpaying for the software firm he founded. HP subsequently took an $8.8bn writedown of Autonomy’s entire value soon after the deal closed, alleging it had discovered “serious accounting improprieties” and blaming Lynch for perpetrating a $5bn fraud, an accusation he denied.

The 59-year-old billionaire was cleared by a Californian court on 6 June of all 15 counts of fraud, which meant he avoided facing up to 25 years in a US prison.

“I have various medical things that would have made it very difficult to survive, Lynch told the Sunday Times. “If this had gone the wrong way, it would have been the end of life as I have known it in any sense.”

Lynch, who said he “never watched anything with prisons in it” during the 13 months he spent under house arrest in San Francisco after his extradition in May last year, said he was keen to fund a British equivalent of the Innocence Project, a US nonprofit that works to gain the release of people it believes have been wrongfully convicted.

“The system can sweep individuals away,” he said. “There needs to be a contrarian possibility that’s saying: ‘Right, well, the whole world thinks you’re guilty but, actually, was that a fair conviction?’”

Lynch, a science adviser to David Cameron when he was prime minister and a former non-executive director of the BBC who received an OBE for services to enterprise in 2006, spent two years fighting extradition to the US to face trial.

Another item on his to-do list is to seek to address the imbalance he believes there is in the extradition treaty between the UK and the US. “It has to be wrong that a US prosecutor has more power over a British citizen living in England than the UK police do,” he said.

After landing in the US, Lynch was accompanied by the United States Marshals Service and a court ordered him to pay a $100m bond and called in 24-hour armed guards, deeming the billionaire to be a flight risk.

However, Lynch’s battle with HP continues in the UK. In 2022, HP won a six-year civil fraud case against Lynch after a high court judge ruled that he had defrauded HP by manipulating Autonomy’s accounts to inflate the value of the company.

Mr Justice Hildyard, the high court judge in the case, is expected to rule on HP’s claim for $4bn in damages. The judge has said the level of damages he intends to award will be much lower.

Lynch, who said that his finances were not in a “perilous situation” because of successful tech investments made by his wife on his advice, intends to appeal when the award is made.