It would be "very regrettable" if newspapers tried to challenge cross-party plans for a new system of press regulation through the courts, Labour deputy leader Harriet Harman has said.
Ms Harman said that the industry should not seek to boycott plans to establish a new regulatory system through a royal charter passed by the Privy Council.
The representatives of the three main parties agreed a series of changes to the proposed charter intended to make it more palatable to the industry and encourage newspapers to sign up.
But a newspaper industry steering group last night made clear that the amendements failed to meet their fundamental objections, saying it was neither voluntary nor independent.
"This remains a charter written by politicians, imposed by politicians and controlled by politicians. It has not been approved by any of the newspapers or magazines it seeks to regulate," it said.
There have been reports that there could now be a legal challenge to the decision earlier this week by the Privy Council to throw out an alternative charter put forward by the industry.
However, Ms Harman, who represented Labour at the cross-party talks, said the press should now accept the verdict of the politicians and not try to challenge it through judicial review.
"I think it would be very regrettable because I think that it would be much better for them just to join in to the framework that has already been set forth. It's no danger to them at all," she told the BBC Radio 4 Today programme.
"For them to boycott it and say 'We are going to set up our own system' ... I think leaves us exactly where we were before which is the press are marking their own homework."