THE phone hacking scandal engulfing the News of the World intensified last night amid claims that thousands of people could have been affected.

A lawyer representing several of the celebrities involved said there could be up to 7000 victims.

It came as Gordon Brown was drawn into the scandal for a second time amid claims from an unnamed former minister that Rupert Murdoch, the paper’s owner, had asked the then prime minister to “defuse” the growing row. The claim has been denied by the newspaper’s publisher.

Yesterday the tabloid printed an prominent apology for hacking into the voicemail messages of celebrities, politicians and members of the public.

“Here today, we publicly and unreservedly apologise to all such individuals,” it read, adding that the hacking “was and remains unacceptable”.

But the apology did little to calm the growing row.

The Shadow Welsh Secretary, Peter Hain, called for a “full and proper public investigation” into the scandal as he accused the original police investigation of being “tardy”.

On the other side of the political fence, LibDem Cabinet minister Danny Alexander said that the current police investigation “must go forward” describing the hacking as “a very serious scandal”.

“It’s outrageous that people have had their voicemails hacked into, seemingly a large number of people,” he said, although he added that the scandal had no bearing on Mr Murdoch’s attempt to take over broadcaster BSkyB.

Lawyer Charlotte Harris, whose clients include Sky Andrew, the football agent, predicted that up to 7000 people could be involved.

She said: “If you consider that if you hack into one person’s phone, you have access to everyone who has left a message for them. And then, if you go into the person who has left a message, you get all of theirs.”

Although the newspaper has also said it will pay compensation to those affected, a number of high-profile victims are understood to reject that offer and are demanding full disclosure about the paper’s activities.

Hollywood actress Sienna Miller’s lawyers confirmed that she would continue to pursue her legal case against the newspaper.

It was revealed in January that Mr Brown had contacted police amid fears that he too could have had his phone hacked while he was chancellor.