Claims of collusion over HP’s proposed settlement with shareholders regarding its botched Autonomy acquisition go "beyond the pale", according to the tech giant’s latest court filing.

Ex-Autonomy CFO Sushovan Hussain has attempted to scupper Hewlett-Packard’s deal with its investors by calling it collusive, as HP tries to bury the hatchet with shareholders and jointly sue Hussain and ex-Autonomy CEO Mike Lynch.

But HP yesterday called on Judge Charles R. Breyer to reject Hussain’s efforts to derail the settlement before the judge decides whether or not to approve it later this month.

The settlement would see investors ditch lawsuits suing HP over its $8.8bn write down of its $11bn purchase of British software maker Autonomy in 2011.

HP claims Autonomy execs misled it over the true value of the company, but Hussain and Lynch say HP merely wrongly predicted the value of buying the company.

Judge Charles R Breyer already rejected the initial proposed settlement, which would have seen $48m paid to law firms, late last month, saying a revised settlement must be proposed that avoids payments to shareholders’ lawyers and instead focus on how HP can improve future acquisition practice.

Hussain claimed the deal, hatched by shareholders’ lawyers with HP and mediated by retired District Judge Vaughn Walker, was collusive.

But HP lawyers wrote in yesterday’s filing: "Hussain’s suggestion that, by agreeing to arbitrate this fee dispute, Judge Walker is once again colluding with the parties, is beyond the pale. His suggestion that there is some secret side deal is, likewise, pure fabrication. There is no side deal."

They additionally claimed that Hussain was trying to block the deal simply to preview the case HP is preparing against him – having filed documents to the US Department of Justice, the Securities and Exchange Commission and the UK’s Serious Fraud Office.

The filing added: "Hussain can spin his version of an alternate reality when he is sued, or when a criminal case is brought against him."

A blog post from Autonomy’s former execs last week reiterated their claims that the firm was completely open about its accounts with independent auditors at the time of the HP deal.

It said: "Autonomy’s management cannot be held responsible for HP’s excessive forecasting of synergies [the amount of joint extra generated revenue HP could expect from buying Autonomy].The write off is due to HP’s own recklessness and not due to any accounting improprieties."

An HP spokeswoman responded by saying: "The proposed settlement provides valuable benefits to HP shareholders and allows the company to move forward with its claims against the true perpetrators of the fraud against the company.

"Former senior Autonomy management engaged in a brazen scheme of deception to inflate revenues and growth in Autonomy’s publicly filed financial statements over multiple years, and when confronted by HP repeatedly hid the truth. HP will hold them accountable for their actions through the appropriate legal channels."

HP claims its revised settlement meets court demands.