David Cameron has dramatically pulled the plug on efforts to reach cross-party consensus on press regulation, announcing he will bring the matter to a head by forcing a vote in the House of Commons on Monday.
In a move which surprised both Ed Miliband and Nick Clegg, the Prime Minister said he will publish a Royal Charter to underpin a new self-regulatory system for the press without the need for parliamentary legislation.
Mr Cameron was accused of a "shameless betrayal of victims of press abuse" by the Hacked Off campaign, which is pushing for full implementation of last year's Leveson Report recommendations, including an independent regulator underpinned by statute. But he insisted that the Conservative proposals provided "the fastest possible way" to deliver "the toughest press regulation that this country has ever seen".
And his initiative was welcomed by representatives of some of the UK's biggest newspaper groups, who said they shared the PM's frustration at the cross-party talks being "hijacked" by advocates of legislation. Both Labour and Liberal Democrats said they will "reach out" to Tory MPs to build cross-party agreement ahead of Monday's vote.
Mr Cameron's amendment to the Crime and Courts Bill will not provide statutory underpinning for the new regulator, but will allow courts to impose "exemplary damages" on newspapers which refuse to sign up to the system. Mr Cameron regards this financial incentive as absolutely central to his Royal Charter scheme, and it is thought unlikely that he would press ahead with it if he loses Monday's vote.
Senior Conservative MP John Whittingdale, who chairs the Commons Media Committee, said there was a "strong chance" that Mr Cameron will be defeated in the Commons.
Even if his amendments to the Crime and Courts Bill are approved by the Lower House, he still faces a tough fight in the Lords, where peers have shown themselves more open to the option of legislation.
The Prime Minister made clear he expects Tory MPs to back his proposals, and said that other parties could either "back my amendments... and secure a workable new system that delivers the principles of Leveson's recommendations or they can grandstand and end up with a system that I believe will not work".
Mr Cameron informed the Labour and Lib Dem leaders of his plans in a 10-minute phone call on Thursday morning, less than half an hour after Deputy Prime Minister Mr Clegg told a radio phone-in he was still hopeful of achieving cross-party agreement.
In a hastily-arranged press conference at 10 Downing Street, Mr Cameron cited Churchill's characterisation of the free press as "the most dangerous foe of tyranny" and promised he would defend it from political interference.