No charges will be brought following a probe into phone hacking at the News of the World, prosecutors have confirmed.
The director of public prosecutions Keir Starmer said there was no admissible evidence to support claims public figures' phones were hacked.
An ex-reporter on the paper refused to comment to police about claims he made in the US that his former boss Andy Coulson knew about the practice.
Tory communications chief Mr Coulson denies knowing anything about hacking.
Mr Starmer said former NoW reporter Sean Hoare refused to co-operate with police over claims he made in the New York Times that the practice was more widespread at the UK newspaper than had been previously admitted.
He said: "A number of other witnesses were interviewed and either refused to co-operate with the police investigation, provided short statements which did not advance matters, or denied any knowledge of wrongdoing.
"Against that background, there is no admissible evidence upon which the CPS (Crown Prosecution Service) could properly advise the police to bring criminal charges."
Any further allegations would be investigated by a panel of police officers and prosecutors, he added.
Scotland Yard said the police investigation would remain closed.
A spokesman said the advice it received from the CPS was that there was insufficient evidence to provide a "realistic prospect" of conviction.
Mr Coulson was editor of the tabloid newspaper when its royal editor, Clive Goodman, was jailed for conspiracy to access the phone messages of Prince William and Prince Harry.
Labour MP Chris Bryant - who believes he was also targeted by hackers - has said it is "inconceivable" Mr Coulson did not know what his reporters were doing.
The Standards and Privileges Committee is investigating claims he and other MPs may have been targeted.
The Commons Home Affairs Select Committee is also conducting an inquiry into hacking and the police response to the claims.
Giving evidence in the perjury trial of former MSP Tommy Sheridan, Mr Coulson admitted his reporters did not "get it right" in Goodman's case.
But he was confident the police would find no evidence that he was aware of illegal phone hacking at the paper, he told the High Court in Glasgow on Friday.
Mr Coulson denied that he had been given a pay-off to keep quiet by the News of the World.
In July 2009, the Guardian newspaper claimed NoW journalists were involved in the phone hacking of up to 3,000 celebrities, sports stars and politicians.
Its list included former Deputy Prime Minister Lord Prescott, former Culture Secretary Tessa Jowell, celebrity cook Nigella Lawson, actress Gwyneth Paltrow, London Mayor Boris Johnson, comedian Lenny Henry, singer George Michael and the late reality TV star Jade Goody.
The paper also said it had evidence that News Group Newspapers - owner of the NoW - had paid £1m to settle legal cases that might have revealed evidence of illegal activities.