PRIME Minister David Cameron today promised action to "get to the bottom" of the phone hacking scandal but said it was not just about the press but about the police and "about how politics works too".

Mr Cameron spoke out as as shockwaves from the scandal, which forced the closure of the 168-year-old News of the World last night, continued to reverberate.

He said a judge would be appointed to run an independent inquiry into how the scandal was allowed to happen, adding: "No stone will be left unturned."

Mr Cameron said a second inquiry would be held to examine the ethics and culture of the press and said that the Press Complaints Commission had failed, adding: "I believe we need a new system entirely."

Accepting some of the blame, Mr Cameron said party leaders "were so keen to win the support of newspapers we turned a blind eye to the need to sort this issue".

His comments came as his former communications chief and News of the World editor Andy Coulson was facing arrest over alleged phone hacking and illegal payments to police officers.

Mr Cameron said the decision to hire Mr Coulson was "mine and mine alone", adding: "I take full responsibility for it."

The Prime Minister said the bulk of the first inquiry, which would also cover other newspapers and the failure of the first Scotland Yard investigation into phone hacking, could not be carried out until after the new police probe was complete.

But he said a second inquiry would begin immediately into the culture, ethics and practices of the British press.

"Police investigations can only get you so far," he told a Downing Street press conference.

"What people really want to know is what happened and how it was allowed to happen.

"That is why the Deputy Prime Minister (Nick Clegg) and I have agreed it's right and proper to establish a full public inquiry to get to the bottom of what happened.

"A judge needs to be in charge so there is no question that its totally independent and things are done properly."