Cross-party unity on Lord Justice Leveson's to reform press regulation appeared to be sliding away this weekend.
Hardening rhetoric on both sides and Ed Miliband's introduction of a Christmas deadline on the cross-party attempt to secure consensus led to growing fears that unity would prove impossible to achieve.
Pro-reform campaigners have been encouraged by the rapid growth of the petition backing Leveson's proposals, which was approaching 100,000 signatures by Sunday morning.
Hugh Grant said he feared "vested interests" were influencing those in power from complete implementation of Leveson's principles. The judge recommends the establishment of independent self-regulation of the press backed by statutory underpinning.
"If the prime minister did not wish to change the regulatory system even to the moderate, balanced and proportionate extent proposed by Lord Leveson, I am at a loss to understand why so much public money has been spent and why so many people have been asked to relive extremely painful episodes on the stand in front of millions," author JK Rowling wrote in an article for Saturday's Guardian newspaper.
"Having taken David Cameron's assurances in good faith at the outset of the inquiry he set up, I am merely one among many who feel duped and angry in its wake."
Labour, the Liberal Democrats and most of parliament's smaller parties support Leveson's reforms, setting up the possibility that the Conservative party could be defeated on the issue if it comes to a vote.
Cameron's hand has been strengthened by the intervention of civil liberties champion Shami Chakrabarti, however.
The Liberty director, a member of Leveson's advisory panel, warned that the proposal to make Ofcom a 'backstop regulatory' would violate article ten of the European Convention on Human Rights if it was passed into law.
"A compulsory statute to regulate media ethics in the way the report suggests would violate the Act, and I cannot support it," she told the Mail on Sunday newspaper.
"It would mean the press was being coerced in being held to higher standards than anyone else, and this would be unlawful."
Cross-party talks could lead to some elements of Leveson's proposals, relating to their impact on investigative journalism and contact between journalists and their sources, dropped.
But Miliband used an interview with the Observer newspaper to raise the stakes by demanding that unity is reached by Christmas.
"I think there is huge urgency," he said.
"We're not going to let these talks become a smokescreen for inaction and just be used as a way to run this into the ground, hoping people forget all about it, and hoping the fuss dies down.
"So in the next two to three weeks we have got to have a resolution."
Chancellor George Osborne said all politicians wanted to see the Leveson principles implemented by newspapers, but said he thought Chakrabarti "spoke very powerfully".
"Let's try and carry on talking on a cross-party basis. I don't think we should be setting deadlines before Christmas."
Shadow chancellor Ed Balls said on the same programme: "Doing this in a divisive way is a bad thing, but it requires the prime minister to lead."