LONDON (Reuters) – British entrepreneur Mike Lynch vigorously denies new U.S. criminal charges against him, his spokesman said on Saturday ahead of a court case over the sale of his firm Autonomy which will begin in London next week.

U.S. prosecutors on Friday added three new criminal charges to their indictment against Lynch related to the $11.1 billion sale of his software company Autonomy to Hewlett-Packard in 2011.

Lynch faces a new charge of securities fraud, which carries a maximum prison term of 25 years, as well as additional charges of wire fraud and conspiracy in the 17-count indictment filed with the federal court in San Francisco.

“These are baseless, egregious charges issued on the eve of the trial in the UK, where this case belongs, and Dr Lynch denies them vigorously,” a spokesman for Lynch said.

Mike Lynch, once hailed as Britain’s answer to Bill Gates, faces Hewlett-Packard (HP) in London’s High Court on Monday in a multi-billion dollar showdown over the U.S. technology company’s 2011 purchase of Autonomy.

HP is accusing Lynch and former Autonomy Chief Financial Officer Sushovan Hussain of involvement in accounting irregularities that caused it to overpay for the company.