The News International phone-hacking saga threatens to retoxify the Tory brand. Cameron needs to be ruthless to save his reputation

David Cameron’s closeness to the News International elite and his hiring of Andy Coulson have posed real and serious problems for the PM as the phone-hacking story continues to unfold. Tim Leunig argues that Cameron needs match Rupert Murdoch’s ruthlessness in taking on the media giant and preventing the scandal from retoxifying the Conservative Party.