Explain yourself, Autonomy founder tells HP over 'impropriety' claim

Autonomy founder Mike Lynch last night stepped up his battle with Silicon Valley giant Hewlett-Packard, demanding that the company divulge details of its allegations against him, a week after it went public with claims of financial impropriety.

"Having no details beyond the limited public information provided last week, and still with no further contact from you, I am writing today to ask you, the board of HP, for immediate and specific explanations for the allegations HP is making," the technology entrepreneur wrote in an open letter to the company which acquired his £6.7 billion data-sorting firm 15 months ago.

The deal descended into bitter recrimination last week when HP wrote off £5.5bn – much of it linked to Autonomy – and new boss Meg Whitman said that an internal investigation had found what appeared to be a "wilful effort on behalf of certain former Autonomy employees" to inflate the value of the company

Mr Lynch, who earned £500m from the takeover, departed in May, but immediately took to the airwaves to defend himself.

"I have been truly saddened by the events of the past months, and am shocked and appalled by the events of the past week," he said in the letter. "I believe it is in the best interests of all parties for this situation to be resolved as quickly as possible."

He also posed several questions, including: "Can HP really state that no part of the $5 billion writedown was, or should be, attributed to HP's operational and financial mismanagement of Autonomy since the acquisition?" and "How many people employed by Autonomy in September 2011 have left or resigned under the management of HP?"

HP rejected Mr Lynch's request for further details, saying it believed "the legal process is the correct method in which to bring out the facts and take action on behalf of our shareholders".

The fresh sparring comes after HP was hit with a class-action lawsuit in the US by an investor who claimed the company knew statements about the acquisition of Autonomy were misleading and led the stock to fall.