LONDON (AFP) - An inquiry into the ethics of the British press opened Monday, with a judge vowing to find out "who guards the guardians" in the wake of the News of the World phone-hacking scandal. Some four months after a flood of hacking allegations shocked the nation and prompted the closure of the Rupert Murdoch-owned News of the World, the public inquiry into the press led by judge Brian Leveson formally got under way. Prime Minister David Cameron ordered the investigation after the current system of self-regulation failed to identify rogue practices at the Sunday tabloid, which was Britain's biggest selling weekly newspaper.