New details of claims by United States technology giant Hewlett-Packard against former directors of the Cambridge-based Autonomy group, which HP acquired for 11billion US dollars in 2011, have been branded as a “search for a scapegoat”.

HP, which subsequently wrote-down most of the value of the UK company, has launched legal action in California, accusing Autonomy of artifcially inflating its revenues ahead of the deal, so resulting in HP paying more than the business was worth.

It is seeking to recover 5.1bn US dollars (about £3.6bn) from Autonomy’s founder and former chief executive, Mike Lynch, who lives in Suffolk, and the company’s former chief financial officer, Sushovan Hussain.

Documents now filed with the court in California allege that Autonomy’s revenues were overstated during a two-and-a-half-year period from 2009 to 2011, which HP says resulted in it overpaying by an estimated £3.2bn.

However, in a preliminary response to the allegations, lawyers acting for Dr Lynch insist that Autonomy was “in full compliance” with the law and the applicable accounting standards and that it employed “a professional and experienced finance team that paid careful attention to ensuring that its accounts were properly stated”.

They also say in a letter to HP that Autonomy was “transparent” in its dealings with its auditors (from the accountancy firm Deloitte), that the auditors continue stand by the accounts, and that Dr Lynch had little personal involvement either in sales or in the corresponding accounting decisions.

“Accordingly, it should not be surprising that there is not one shred of actual evidence establishing any pre-acquisition misconduct by anyone at Autonomy, let alone evidence of fraud,” the letter adds.

On a blogsite maintained by Dr Lynch on behalf of the former management team at Automony, he said: “HP’s claim is finally laid bare for what it is – a desperate search for a scapegoat”.

He added: “The contents of the claim are a simple re-hash of previous leaks and insinuations that add up to one long disagreement over accounting treatments, and have nothing to do with fraud.”

Earlier this year, the UK’s Serious Fraud Office (SFO) closed an investigation into the sale of Autonomy, stating that there was “insufficient evidence for a realistic prospect of conviction”.

The SFO ceded legal jurisdiction to authorities in the US, although the lawyers for Autonomy’s former directors argue that any proceedings belong in a British court.