The ex-CFO of Autonomy hopes to block HP’s proposed settlement with shareholders over its controversial £6.5bn acquisition of the software maker.

Sushovan Hussain claimed the deal between HP and shareholders to bury the hatchet over the disastrous 2011 acquisition is "collusive and unfair" in a court filing yesterday.

He wrote that if a federal judge approved the settlement, HP could "forever bury from disclosure the real reason for its 2012 write-down of Autonomy: HP’s own destruction of Autonomy’s success after the acquisition".

The settlement deal reached on June 30 would see shareholders drop their claims against existing and previous HP execs and help the company pursue lawsuits against various Autonomy execs.

Hewlett-Packard’s acquisition of Autonomy triggered government investigations after it wrote off £5.15bn of the purchase price in 2012, claiming it had found serious accounting irregularities in Autonomy’s books.

Autonomy’s founder and CEO, Mike Lynch, was then ousted from HP in May 2012, but has denied any wrongdoing.

HP spokesman Howard Clabo responded to Hussain’s filing by calling it "baseless".

"Mr. Hussain’s opposition to the settlement is baseless," he said. "We strongly believe that at the end of the process, the jury will conclude that Mr. Hussain engaged in a multi-billion dollar fraud."

Hussain’s filing also said that shareholders’ lawyers were performing an ‘about-face’, downplaying their failure to target Autonomy as ‘immaterial’ at a previous hearing in September 2013, but now – under the terms of the settlement – pursuing those executives.