Scotland Yard was under intense pressure last night to reopen its investigation into phone hacking by journalists amid claims that former British prime minister Gordon Brown may have been among the victims.
Senior politicians from both government and opposition demanded that police fully investigate the latest allegations that the mobile phones of prominent public figures had been illegally targeted.
Labour deputy leader Harriet Harman said the law must be enforced, while the Lib Dem energy secretary Chris Huhne said it was "implausible" to claim the practice was confined to "one rogue reporter" at the 'News of the World'.
Their comments came as it was reported that Mr Brown had written to the Metropolitan Police Commissioner expressing concern that his voicemail messages may have been broken into.
The former prime minister is the most senior public figure to be drawn into the controversy, which last week saw Andy Coulson resign as David Cameron's director of communications amid continuing allegations of phone hacking by reporters at the 'News of the World' when he was editor of the paper.
Mr Brown's office would not comment on the reports, while Scotland Yard also declined to respond. However, Ms Harman said that the police had a clear duty to uphold the law.
"Hacking into people's phones is illegal. Obviously the criminal law has got to be complied with and if it is broken then it should be investigated by the police and it should be enforced," she said.
"Nobody is above the law, no newspaper editor, no journalist."
Mr Huhne said that it was clear that the practice extended far beyond the 'News of the World's' former royal correspondent Clive Goodman, who was jailed in 2007 along with private investigator Glenn Mulcaire.
"Why would the royal correspondent be interested in hacking the voicemails of (Lib Dem deputy leader) Simon Hughes, for example?" he asked.
"It is very important for Paul Stephenson, having now taken control of the Met, to make sure that, along with the Crown Prosecution Service (CPS), this is really dealt with.
"I have worked on a newspaper. . . and it does seem to me totally implausible that this was a situation where it was limited to one journalist."
Scotland Yard formally closed its investigation into the allegations against the 'News of the World' last month.
However, a number of public figures are continuing to pursue civil legal actions against both the newspaper and the police, prompting a series of fresh disclosures.
Earlier this month, the Met announced that it was passing all its evidence to the Director of Public Prosecutions for lawyers at the CPS to review.
There has been growing criticism at the apparent reluctance of the police to pursue the case more vigorously.
Tony Blair's former communication chief Alastair Campbell described the Met's handling of the case as "extraordinary" and a "scandal".