Rupert Murdoch's News International took active steps to delete and prepare to delete the publisher's email archives as phone-hacking allegations and lawsuits against the owner of the now-defunct News of the World mounted in 2009 and developed in 2010.

According to court documents filed by victims of hacking, the newspaper publisher allegedly produced an email deletion policy in November 2009 whose aim was to "eliminate in a consistent manner" emails "that could be unhelpful in the context of future litigation".

An unnamed senior executive at News Group Newspapers, the News International subsidiary that publishes the Sun and the News of the World, also repeatedly demanded progress on the "email deletion policy" during 2010, asking on 29 July: "How come we still haven't done the email deletion policy discussed and approved six months ago?"

According to the claimants, News International also destroyed "all computers used by its journalists" in about October 2010 – including one machine of a reporter named specifically in actor Sienna Miller's action, while in January 2011 all emails on its archive system up to 31 September 2007 were deleted according to a witness statement from NI's recently appointed chief information officer. Hacking is primarily understood to have taken place between 2002 and 2006.

The timing of the alleged deletion activity – contained in high court documents underlying celebrity hacking cases and which were released to the Guardian yesterday – is significant because it took place as accusations of widespread phone hacking first appeared and subsequently as legal actions against the News of the World developed.

In July 2009 the Guardian published its first exposé of the phone-hacking scandal, which said that thousands of people may have been targeted by the News of the World until the 2006 arrest of Clive Goodman, the newspaper's former royal editor, and its £100,000-a-year private investigator Glenn Mulcaire.

Phone-hacking civil suits followed, with a case brought by Max Clifford being settled privately in early 2010 following a Mayfair lunch between the PR veteran and News International's then chief executive Rebekah Brooks.

Specific requests for deletions allegedly came after the company received a letter dated 6 September 2010 from Miller's legal team that demanded that all relevant documents and emails be preserved by Murdoch's News Group Newspapers.

Three days later, on 9 September, an employee in the technology department wrote: "If the deletion need [sic] to wait until tomorrow, then that is fine. There is a senior NI management requirement to delete this data as quickly as possible but it need to be done with commercial boundaries."

Last month, the high court heard that News Group Newspapers had agreed – for the purposes of resolving hacking settlements with the likes of Jude Law and Ashley Cole – that "senior employees and directors" knew about phone hacking and sought to conceal by "destroying evidence of wrongdoing, which evidence included a very substantial number of emails" and the computers of three journalists which had been used when Mulcaire was employed under contract by the News of the World.

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