There may be a case for HM Inspector of Constabulary to be called in to investigate allegations relating to phone-hacking by journalists at the News of the World, shadow home secretary Alan Johnson has said.
Mr Johnson said he will be going to the Home Office to review papers on the case dating from his time as home secretary before offering his advice on the issue to his Conservative successor Theresa May.
Fresh questions have been raised about the interception of private voicemail messages of prominent people - which led to the jailing of a News of the World reporter and a private investigator in 2007 - following a report this week in the New York Times.
The report included claims that then editor Andy Coulson, now a senior adviser to Prime Minister David Cameron, was aware that the illegal practice was being undertaken by journalists on his staff - something Mr Coulson has always denied.
It also raised questions about how vigorously the Metropolitan Police had pursued the case.
Last year, the Met chose not to launch an investigation into claims made by the Guardian newspaper that a series of public figures had been the victims of eavesdropping.
Royal correspondent Clive Goodman and private investigator Glenn Mulcaire were the only people to be prosecuted in relation to phone-tapping, and the News of World has always insisted that theirs was an isolated case.
Former deputy prime minister Lord Prescott said on Friday morning he was prepared to take legal action to force the police to inform him whether his phone was one of those allegedly hacked into.
Lord Prescott said he had demanded the truth about the claims from police and was expecting a reply by September 11.
"If they fail to give us that information, which is clearly available but has to be given to us, I will seek a judicial review," he told BBC Radio 4's Today programme. "The only way the truth can come out is really to have it properly investigated and really have a judicial review. I think it demands at least that."