Lord Justice Leveson has called for legislation to underpin a "genuinely independent and effective system of self-regulation" for the press.
In his report on press standards and ethics, he said legislation would provide "an independent process to recognise the new self-regulatory body and reassure the public that the basic requirements of independence and effectiveness were met".
The judge said the press had ignored its own code of conduct in a way that had "wreaked havoc with the lives of innocent people" on far too many occasions over the last decade. He said there had been a "recklessness in prioritising sensational stories" irrespective of the harm that may be caused.
And he said politicians of all parties had developed "too close a relationship with the press in a way which has not been in the public interest".
His findings, based on months of dramatic evidence about the phone-hacking scandal from victims, media figures, politicians and the police, were published after divisions in the coalition Government over press regulation burst into the open.
Deputy Prime Minister Nick Clegg will make an unprecedented separate statement to the House of Commons after David Cameron responds to the Leveson Report.
The Liberal Democrat leader is understood to favour statutory underpinning, while the Prime Minister is believed to be more wary of involving the state in policing newspapers.
Downing Street and Liberal Democrat sources sought to play down the significance of separate statements.
But the failure to agree on a single message suggests it will be much more difficult to achieve cross-party consensus on Leveson, which both Mr Cameron and Labour leader Ed Miliband backed at Prime Minister's Questions in the Commons on Wednesday.