Prime Minister David Cameron's former communications chief, Andy Coulson, may face further questioning about his role in the hacking affair.

Coulson was, until the beginning of this year, the prime minister's communications chief after quitting his job as editor of the News of the World amid the early hacking revelations.

The Guardian website reports: “He had been the editor of Britain's most-read Sunday newspaper. But this week, News International, Andy Coulson’s former employer, suggested he might face further questions about his own role in the hacking affair.

“On Tuesday, News International indicated that it was aware of ‘worse’ allegations than the suggestion that the News of the World had hacked into the mobile phone belonging to Milly Dowler, and that more would come in the evening.

“It turned out that the subject of the allegations was Coulson, once a fellow rising star and close friend of Rebekah Brooks when she edited and he was her deputy at the News of the World.

“It fell first to the BBC's business editor, Robert Peston – a close friend and former colleague of Rebekah Brooks' number two, Will Lewis – to reveal on the Ten O'Clock News that ‘News international has uncovered emails that indicate payments were made to the police by the News of the World, during the editorship from 2003 to 2007 of Andy Coulson’.

“This came at the moment that the Dowler allegations were being adding to by new reports that families of the victims of the 7/7 bombings were also targeted.”

“That was followed by The Guardian's report that News International had established that Brooks was on holiday in Italy when the controversial Milly Dowler news story appeared:  Coulson would have normally edited the paper in her absence. However former staffers at the tabloid also recall that Brooks usually got her office to fax her proofs of the newspaper to examine while she was away.”

The Guardian website continued: “The question marks about Coulson may have emerged at a moment of crisis for Brooks, but the rupture between the News International chief executive and Coulson has been brewing for some months.

“Brooks has been criticizing Coulson with surprising candour in private meetings. She and other senior figures at the company – such as Les Hinton, the former chairman of News International who is now chief executive officer of Dow Jones & Company – were unhappy that Coulson was so wedded to such a high-profile role.

“News International sources said Coulson had told Hinton that he would only work for Cameron in opposition, and not make the transition to government – where his continued presence gave an additional justification to the phone-hacking story.

“Coulson started working for the Tories in 2007 after he resigned as editor of the News of the World after the conviction of Clive Goodman, its former royal editor, for hacking Prince William's phone.

“One source said of Coulson: ‘This whole business would not be moving like this if Andy had not gone into Downing Street. Andy told Les Hinton that he would not go into Downing Street after the election. Why did he go? It was hubris. The Cameroons made the classic mistake of underestimating their enemies. They didn't think Labour would go for this."

“News International insists that it did not undermine Coulson when it issued a statement to Vanity Fair on Tuesday confirming that it had passed emails to the police showing that Coulson knew of payments to police officers.

“Simon Greenberg, the News International spokesman, said it was important to explain that the emails had been handed to the police because Vanity Fair was suggesting that the company was sitting on the emails.

"It is wrong to say we are hanging Andy out to dry," the source said. "We are just going through the evidence and passing anything on as soon as we see anything."

Downing Street said that the prime minister still stood by a supportive statement he made when Coulson resigned as his communications director in January.