Mike Lynch, the British software tycoon, has been extradited to the US weeks after losing a long-running legal battle against the move.
Sky News understands that Mr Lynch arrived in San Francisco on a United Airlines flight on Thursday lunchtime, paving the way for the former Autonomy chief to be tried on criminal charges.
One source said a judge in California had ordered that he pay a $100m bail bond in order to secure his release during a hearing after his arrival in the US.
Mr Lynch’s extradition had been anticipated since he lost a High Court fight last month.
He has found himself mired in litigation for years, after HP alleged that he and a number of colleagues had manipulated Autonomy’s accounts to inflate its value.
The company’s former finance chief, Sushovan Hussain, is serving five years in prison after conviction in the US in 2018.
Mr Lynch has argued that Autonomy’s status as a British company, listed in London, meant that any charges against him should be brought in the UK.
A civil case against Mr Lynch resulted in HP “substantially succeeding” in its claims in January last year, although Mr Justice Hildyard said it was likely that the resulting damages would be lower than the $5bn being claimed by the American software giant.
The businessman’s fate has sparked a row in which prominent British entrepreneurs and executives have protested at what they called the “unreasonable” use of the extradition treaty between Britain and the US.
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In a letter to Rishi Sunak in February, figures including Brent Hoberman, the co-founder of Lastminute.com, and FTSE-100 boardroom veterans such as Lord Stevenson of Coddenham, the former HBOS and Pearson chairman, argued against the move to have Mr Lynch face trial in the US.
They said it would see a treaty “enacted swiftly after 9/11 to enable the pursuit of terrorists deployed to settle a commercial case already being considered by the UK courts”.
The group of signatories described this as “deeply worrying to anyone running a business in the UK”.
“This sequence of events would clearly intrude on the sovereignty of the British courts and suggest the US can disregard our laws.”
A spokesman for Mr Lynch declined to comment, while the US Department of Justice has been contacted for comment.