Commercial espionage became a possible motive for phone hacking today after a top City PR firm said attempts may have been made to access the voicemails of executives who were advising on media takeovers.
Citigate Dewe Rogerson has been told that three executives may have fallen victim to the practice in 2005 and 2006, at the height of the News of the World's campaign of illegal phone hacking.
At the time the PR firm, one of the biggest in the City, was dealing with Virgin Media's merger with the cable TV company NTL with the aim of challenging Rupert Murdoch's dominance in pay TV.
Mr Murdoch's News Corp, which has a controlling stake in Sky TV, closed the News of the World last year in the wake of the phone hacking scandal.
Confirming the potential intrusion, a spokesman for Citigate said: "We were told by our mobile provider around 18 months ago that police were investigating allegations that between 2005 and 2006 attempts by unauthorised parties may have been made to hack into three of our company mobile phones.
"We sought further details from the police but there has been no recent follow-up by them."
The spokesman said there was no evidence that Operation Weeting, the Metropolitan Police inquiry into phone hacking, was actively pursuing the Citigate allegation.
However the possibility that messages intended for City figures were intercepted could change the public perception of the hacking scandal. Until now, the assumption had been that the News of the World eavesdropped voicemails only to find stories.
Given that some targets were government media ministers and leading business figures, it is now possible that News Corporation's wider corporate interests were at play too.
In the mid-2000s, Sir Richard Branson, Virgin's founder, and Mr Murdoch fell out over Virgin's attempts to move into television.
Sir Richard revealed last year that police had told him his phone may have been hacked by the News of the World. His right-hand man, Will Whitehorn, Virgin Group's corporate affairs director, is also thought to have been targeted.
Sir Richard has so far remained silent on the hacking, except to say that it was worrying, but in 2006 – after he had been thwarted by BSkyB from buying ITV – he told the Daily Telegraph: "All of us know governments are scared stiff of Murdoch."
As the scandal deepened yesterday, the Independent on Sunday revealed that a report for Trinity Mirror shareholders had found that phone hacking was "systemic" at its national newspapers. The report said six reporters from the Daily Mirror and People were said to have regularly used the technique.
Sir Brian Leveson will issue his report on the press next month. He is expected to recommend some form of statutory newspaper regulation.