See also: Former Telegraph CIO Paul Cheesbrough explains the paper's digital reinvention

Police are questioning whether a change in News International’s email retention policy was part of an effort to conceal widespread phone hacking by the News of the World, a scandal which is threatening Rupert Murdoch’s planned takeover of BSkyB.

The trawl for emails and the questioning of changes in News International’s email retention policy has important implications for IT security and corporate governance professioals, and is likely to see organisations examining their own policies and reminding their staff on acceptable usage and best practice for email.

The last edition of the News of the World was published yesterday, amid a scandal over alleged phone hacking by journalists looking for stories. The paper had been published for 158 years.

Allegations have surfaced that managers at News International, the parent company of the newspaper, asked Indian outsourcer HCL to delete emails relating to phone hacking. Last week, Labour MP Tom Watson said in parliament that there had been an attempt to destroy company data at an HCL storage facility.

HCL said it could not have deleted the emails because it only managed News International’s IT infrastructure, not its data. It said it was “fully co-operating with the Metropolitan Police at the request of News International”.

In 2007, News International ordered a law firm to execute an internal investigation into the alleged hacking, including trawling through company emails. Two years later, former editor Colin Myler told a House of Commons select committee – after his predecessor Clive Goodman was sentenced for illegally accessing voicemails – that "over 2,500 emails were accessed” as part of the internal investigation “because we were exploring whether or not there was any other evidence” to suggest the hacking was widespread. He said no evidence was found.

Les Hinton, chief executive of Dow Jones and a former head of News International, faces tough questions over assurances he made to MPs in 2007 that News International’s internal investigation was rigorous.

Sources at News International have told the Daily Telegraph newspaper that those emails were a “ticking time bomb” of information.

William Lewis, a general manager at News International attempting to investigate the issue, is understood to have come to the conclusion that the emails demonstrated staff had been involved in hacking – as well showing that former editor Andy Coulson was aware of staff making payments to police officers to help with stories, it has been reported. The information was handed to the police last month, apparently leading to Coulson's arrest on Friday.