Prime Minister David Cameron has called a halt to cross-party talks on press regulation, sparking anger from party leaders and victims of media intrusion.
Mr Cameron will instead publish plans for a royal charter to establish a tougher press regulator, on which Parliament will vote on Monday.
Both Labour and the Lib Dems said they were disappointed and surprised.
The two parties had backed statutory underpinning as recommended by the Leveson Inquiry into the press.
The inquiry was set up by Mr Cameron to examine the culture, practice and ethics of the press in the wake of the phone-hacking scandal at the now-defunct News of the World tabloid.
Its 2,000-page report, published in November, found press behaviour was "outrageous" and "wreaked havoc with the lives of innocent people".
It recommended that the press should set up a tough new independent regulator, but the system should be underpinned by legislation to ensure the system was effective.
The report exposed divisions in the coalition government, with Mr Cameron opposing statutory control.
Labour-Lib Dem talks
Many who oppose statutory control feel it could limit freedom of speech, whereas those who back it say self-regulation - the current system of press regulation - has been shown to be ineffective in preventing press intrusion.
BBC political editor Nick Robinson says Labour are now expected to table parliamentary amendments to produce what they describe as "a Leveson compliant royal charter".
Party sources say they expect the Liberal Democrats to vote with them following talks between Labour leader Ed Miliband and Lib Dem deputy prime minister Nick Clegg.
Earlier, speaking at a Number 10 press conference on Thursday, Mr Cameron confirmed cross-party talks on press reform had "concluded without agreement".
He said press treatment of those including the families of missing girl Madeleine McCann and murdered teenager Milly Dowler was "absolutely despicable", stressing he wanted a new system to prevent such things happening.
But he said a full legislative response endangered press freedom.
He said a royal charter would help to create the world's "toughest" regulatory system, which would allow the imposition of "exemplary damages" on newspapers which refuse to sign up.
MPs will be asked to vote on the plans during the passage of the Crime and Courts Bill.
One of the reasons cited by the prime minister for halting the talks was that he felt other bills were being delayed and potentially endangered by efforts to pass Leveson-related legislation.
In the press conference, Mr Cameron said that in recent weeks "those who want, or would prefer, a full legislative approach to Leveson have hijacked important parliamentary bills on other issues", a situation he said he could not allow to continue.
"If other parties do not want to adopt the approach that I am recommending, they will have that option when the Crime and Courts Bill is debated on Monday night," he said.
Mr Cameron's comments came after the three main political parties held face-to-face talks on Wednesday to discuss whether plans for a new watchdog should be underpinned by legislation.
The prime minister is understood to have told Mr Clegg and Mr Miliband by phone on Thursday that he would not accept a press law of any kind.
The deputy prime minister said he was "disappointed and surprised that David Cameron has decided to walk away from the cross-party talks" just when "real progress" was being made.
"Clearly I don't agree with David Cameron's approach. I will be working with politicians... from all parties to make sure we deliver the right solution," he said, adding that press regulation should not be the subject of "party political points scoring".
"David Cameron has decided to turn his back on a cross-party approach. I have not."
And Mr Miliband said the prime minister's solution did not serve the victims of press intrusion as "ministers could change his proposals without reference to Parliament, and it's not properly independent of the press".
He said a cross-party solution could still be reached, even if Labour and the Lib Dems went above Mr Cameron's head to talk to Tory MPs.
Meanwhile, media reform campaign group Hacked Off said the prime minister's announcement "shows that he's still protecting his friends in the press and betraying press abuse victims".
Its director, Prof Brian Cathcart, said the system Mr Cameron wanted to introduce would represent an "appalling betrayal" of the victims of press abuse who gave evidence to the inquiry.
"What David Cameron proposes is not real change. His charter is a complete disappointment, not only to those who gave evidence to the inquiry but the country," he said.
Baroness Sheila Hollins, the mother of Abigail Witchalls who was attacked and became the subject of press intrusion, said she was "extremely angry" that the prime minister stepped away from the talks.
She said Lord Justice Leveson's recommendations "do in fact secure the freedom of the press, but it's the freedom of the press to act in an ethical and responsible way" rather than the freedom for them to work in a way that intrudes on people's lives.
"This is not a party political issue. They should come together and not allow the press themselves to veto some of the proposals that have been made."
In a joint statement, executives of major newspaper publishing groups and press bodies said: "We share the prime minister's frustration at the way in which talks about the future of press regulation have broken down and legislation has been hijacked.
"The prime minister is right to reject statutory regulation of the press - free of political control for 300 years - as fundamentally wrong in principle and unworkable in practice."
BBC deputy political editor James Landale said that on Monday there would be a short "timetable" debate followed by a debate on a government motion in favour of a press regulator underpinned by a royal charter.
"Labour will table an amendment to this motion, setting out their preferred model of a Leveson-compliant royal charter," he said.
Our correspondent added that, depending on the result of that vote, MPs may then go on to debate and vote on detailed amendments to the Crime and Courts bill.