Britain's most senior police officer resigned on Sunday over his relationship with the Murdoch media empire and set off furious speculation after hinting he was quitting to protect prime minister David Cameron.
Scotland Yard chief Sir Paul Stephenson took the step after weekend newspapers in Britain and the US revealed he:
* Awarded a £24,000 public relations contract to Neil Wallis, a former deputy editor at the now-defunct News of the World tabloid, owned by Rupert Murdoch's News International;
* Accepted a £12,000 hospitality to recover from illness at a celebrity health retreat for which Wallis carried out publicity; and
* Met News International executives and editors 18 times over meals during investigations into allegations that newspapers owned by the group had illegally hacked into telephones. Eight of the meetings were with Wallis while he was still with the paper.
In other development, assistant police commissioner John Yates also resigned after being told he would be suspended as his conduct was being referred to the Independent Police Complaints Commission.
Yates came under a cloud after failing to reopen the original 2006 investigation into phone hacking, deciding there was nothing further to act upon.
Also on Monday, Deputy Prime Minister Nick Clegg spoke up for Cameron, saying: "I do not think this is about the Prime Minister's position. The issue about the police is people's fears that a criminal investigation may have been compromised."
Stephenson, a highly-regarded police officer under whom crime fell to a 10-year low in the London region, named both Cameron and the PM's former spokesman Andy Coulson - an ex-Murdoch newspaper editor - in an extraordinary resignation statement.
He said: "I did not want to compromise the prime minister in any way by revealing or discussing a potential suspect who clearly had a closer relationship with Mr Coulson," who was controversially hired by Cameron after he had resigned from the News of the World over the hacking allegations.
The opposition Labour party seized on Stephenson's statement, with its home affairs spokesperson Yvette Cooper declaring: "People will wonder why different rules apply for the prime minister and the Met (Scotland Yard)."
Bail for Brooks
Cameron, who cut short his planned five-day South African trip to half, finds himself in a tricky position.
He was close not only to Coulson, but also to Rebekah Brooks, the former News of the World editor and News International chief executive who was arrested on Sunday and let off on bail after 12 hours of questioning.
Both Rupert Murdoch, who is chairman of the News Corp media conglomerate, and his son James who heads the British arm News International are due to appear before a parliamentary committee on Tuesday in a hearing on the hacking allegations.