The Metropolitan police on Monday admitted the country's most powerful force had become too close to the press and said it would change its relationship with the media.
Addressing Lord Justice Leveson's inquiry into press standards, Neil Garnham QC, representing Scotland Yard, said: "We acknowledge that not all of the MPS's relationships with the press in the past have met the test of being both ethical and transparent."
He said the Met was considering taking steps to ensure senior officers could not work for news organisations after they retired from the force until a suitable period had passed.
Andy Hayman, the former assistant commissioner of the Met who conducted the original 2006 police inquiry into phone-hacking at the News of the World, became a columnist at the Times, which is also part of News International, Rupert Murdoch's UK newspaper arm, shortly after he retired in December 2007.
Hayman used his column to defend the investigation and to claim there was "a handful" of hacking victims.