Police arrested David Cameron\'s former spokesman yesterday over the scandal that has shut down Rupert Murdoch\'s News of the World, forcing the prime minister to defend his judgment while promising sweeping new rules for the British press. As Cameron was fielding hostile questions over why he hired Andy Coulson from the editor\'s chair at the tabloid in 2007, despite knowing that one of his journalists had been jailed for hacking into voicemails in search of scoops, Coulson was being arrested by police on suspicion of conspiring in the practice. Cameron said he took \"full responsibility\" for his decision to hire Coulson, who quit Downing Street in January when police relaunched inquiries. But the premier rebuffed direct criticism and strove to spread the blame for an affair that has generated public outrage against the press, politicians and police. \"Murder victims, terrorist victims, families who have lost loved ones in war...\" he said: \"That these people could have had their phones hacked into in order to generate stories for a newspaper is simply disgusting.\" Article continues below So widespread was the rot, Cameron told an emergency news conference after Murdoch shut down his best-selling Sunday paper, that only a completely new system of media regulation and a full public inquiry into what went wrong over a decade at News of the World would meet public demand. \"This scandal is not just about some journalists on one newspaper,\" Cameron said. \"It\'s not even just about the press. It\'s also about the police. And, yes, it\'s also about how politics works and politicians too.\" While defending himself, the Conservative leader said politicians of all parties had been in thrall to press barons for decades and he indicated a new willingness to challenge the Murdoch empire by withholding overt endorsement of News Corp\'s bid for broadcaster BSkyB . Shares in the pay-TV chain fell 4 per cent after the media ministry said it would take events at the News of the World into account and take its time before giving any approval. Cameron also criticised his friend and neighbour Rebekah Brooks, Coulson\'s predecessor as editor and now a top executive and confidante of Murdoch. She should have resigned, he said, after closing down the newspaper at a cost of 200 jobs. Critics pointed out that many British journalists doubted Coulson\'s assertions that he, as News of the World editor, had known nothing of the hacking of phones used by aides to Prince William — for which royal correspondent Clive Goodman and a private detective were jailed in 2007. Cameron said he had heard that Brooks offered her resignation. \"I would have taken it,\" he said. Labour leader Miliband also said she should go. Both Cameron and Miliband have concluded that a system under which newspaper publishers largely supervise their own code of conduct must be tightened. Cameron said an independent panel could start work within months — much sooner than the public inquiry which must wait for the end of the police case — and that it must be free to draft its own proposals. But he added: \"It should be truly ... independent of the press, so the public will know that newspapers will never again be solely responsible for policing themselves. This new system of regulation must strike the balance between an individual\'s right to privacy and what is in the public interest.\" The police also face tough questions over why an initial investigation into phone hacking was closed after Goodman was jailed in 2007. Detectives are also now looking into payments, in the tens of thousands of pounds, by journalists to police officers, mostly for information.