Scotland Yard last night admitted the discovery of new potential victims of the phone-hacking scandal, opening the way to a wave of further damaging privacy claims by politicians and celebrities against Rupert Murdoch's News International.
In the first sign that the new Metropolitan Police investigation into voicemail hacking at the News of the World is trying to right the failures of its much-criticised predecessor, the officer in charge of the inquiry revealed that new "links" had been found between existing evidence and internal emails handed to police last month by Mr Murdoch's newspaper group.
"Urgent steps" are being taken to inform the new group, all of whom were previously told by the Met that there was "little or no information" held about them on files seized in 2006 from the private investigator Glenn Mulcaire.
Police showed John Prescott, the former deputy prime minister, evidence suggesting that he was targeted in April 2006, the month he admitted to having an affair with his diary secretary Tracey Temple. Deputy Assistant Commissioner Sue Akers, who is leading the new inquiry, briefed him about the case.
In a statement, Mr Prescott said: "She informed me that significant new evidence relating to phone hacking and myself had been discovered and that they were investigating it. I think this proves my long-held belief that the original Met Police investigation into Mulcaire and News International was completely inadequate and failed to follow all the evidence."
Files containing the names and personal details of thousands of individuals were kept by Mulcaire, who was used by the NOTW and jailed in 2007 for listening to the voicemails of aides to Prince William. But civil litigants, such as the actress Sienna Miller, have been forced to go to court to obtain details of the alleged hacking.
In an apparent admission that the initial police investigation, headed by Deputy Commissioner John Yates, had failed to inform all victims of hacking, Ms Akers said: "We are determined to ensure we conduct a robust and thorough investigation... We will be as open as we can be and will show [victims] all the information we hold about them."
Although the Yard declined to discuss how many new potential victims had been identified, her statement that they form an "important and immediate new line of inquiry" will add to News International's headaches.
The newspaper group already faces lawsuits from at least a dozen celebrities, ranging from Ms Miller to the former Sky pundit Andy Gray, and has paid nearly £2m to settle privacy claims from Max Clifford and from Gordon Taylor, chief executive of the Professional Footballers Association.
In 2009, police disclosed that the material seized from Mulcaire's home included 4,332 names or partial names of people; 2,978 mobile phone numbers; 30 audio tapes which appear to contain recordings of voicemail messages; and 91 PIN codes which had changed from the default manufacturer settings.
Solicitor Mark Lewis, who represents some alleged victims, had accused the Met of being "deliberately obstructive" by making them apply for evidence through the courts.
The Labour MP Chris Bryant said: "It's scandalous that the only reason there is this new avenue of investigation is that Sienna Miller got the court to force the Met to release the information they gathered from Mulcaire relating to her all those years ago.
"Until now, it has been the victims that have had to do the investigative work, so it's a welcome development that the police have finally taken on their responsibility."
The Labour backbencher Tom Watson said: "It's shocking to learn that some victims were misinformed, but reassuring that the new team on the case at the Met appear to be getting on top of the investigation."
The latest development in the four-year saga has arisen directly from the decision last month by News International to hand over to detectives an unspecified number of emails following the sacking of Ian Edmondson, the head of news at the NOTW who was employed by Andy Coulson, the paper's editor at the time of the royal hacking scandal.
The dismissal of Mr Edmondson, who has denied any wrongdoing, coincided with the abandonment by News International of its stance that voicemail hacking at the NOTW was restricted to a single "rogue" reporter, the royal editor Clive Goodman, who was jailed with Mulcaire in 2007.
Sources have indicated there is every sign that the new officers assigned to the case are taking a robust approach. The Yard's new statement appears to tally with that: "Having begun an analysis of the documents seized in 2005 alongside the new evidence, the team have been able to make some links not previously identified.
"As a result, the team have also identified individuals who were previously advised there was little or no information held by the Met relating to them within the case papers and exhibits and this is being reviewed.
"At this stage, there is no evidence to suggest their voicemails were hacked but this will be an important and immediate new line of inquiry."
News International declined to comment.