HP has branded the ex-CFO of Autonomy as "one of the chief architects of the massive fraud" that led the firm’s own shareholders to sue the tech giant over the £6.5bn acquisition of the software maker.

Former Autonomy exec Sushovan Hussain issued a court filing last week to say HP’s deal with shareholders over the disastrous 2011 acquisition is "collusive and unfair".

The proposed agreement, seeking court approval, would see shareholders drop their claims against HP execs and help pursue various Autonomy execs.

But HP has now responded with its own court filing, which accuses Hussain of helping cook the books, leading Autonomy to be overvalued to the extent HP was forced to write off £5.15bn of the acquisition in 2011.

HP’s lawyers wrote: "Sushovan Hussain, Autonomy’s CFO from 2001 to May 2012, was one of the chief architects of the massive fraud on HP that precipitated this litigation.

"The notion that he should be permitted to intervene and challenge the substance of a settlement designed to protect the interests of the company he defrauded is ludicrous."

It added that Hussain was seeking to save his own skin, with litigators after him on both sides of the Atlantic, as well as outlining the company’s intent to sue him in England.

"Hussain, the fraudster, wraps himself in a mantle of self-righteousness in an attempt to obtain discovery that he hopes will help him stay out of prison and defend the civil litigation he expects HP will file in the UK," the filing read.