Labour has started work on drafting its own Bill based on the Leveson recommendations for press regulation and will use it as the basis for a Commons vote if David Cameron blocks reform, it has emerged.
The party was frustrated by suggestions that draft legislation the Prime Minister ordered to be drawn up was simply an exercise in showing the plans are unworkable.
It has brought in legal experts to put together proposals within two weeks that would implement the core principles of Lord Justice Leveson's findings, a party source said.
Cross-party talks on the report will resume on Monday with Harriet Harman representing Labour and her opposite number Culture Secretary Maria Miller for the Tories. They will take place before MPs debate the contents of the 2,000 page report, which was published last Thursday.
The Labour source said the party was committed to the talks but warned: "If they are not successful Ed Miliband does want to push this to a vote. This Bill could form the basis of that vote."
The chairman of the soon-to-be-scrapped Press Complaints Commission claimed legislation was unnecessary, calling for five-year rolling contracts instead to ensure publications could not "walk away" from a new regime.
Lord Hunt, who will take part in talks between the Prime Minister and Fleet Street next week, said newspapers were set to sign up to a new independent press watchdog voluntarily. He told Sky News: "I have spoken to 120 publishers speaking on behalf of 2,000 editors. They have all told me they will sign up."
Concerns have been raised over the legality of Lord Justice Leveson's calls for a last resort option of compulsory press reform laws because it would "coerce" newspapers into holding higher standards than anyone else.
Shami Chakrabarti, one of six assessors who worked with the judge on the inquiry, said she could not support any legislation that was forced on the press and claimed it could breach the Human Rights Act. But the director of civil rights group Liberty warned the report's nuclear option of compulsory regulation if the press failed to sign up voluntarily could have "serious unintended consequences".
She told the Mail on Sunday: "A compulsory statute to regulate media ethics in the way the report suggests would violate the Act, and I cannot support it. It would mean the press was being coerced in being held to higher standards than anyone else, and this would be unlawful."