The former executive editor of the New of the World Neil Wallis has said that some politicians support legislation on press regulation as "revenge after the [MP] expenses scandal".
He was the British press was being "neutered".
A man who won libel damages after his arrest over the murder of a woman has written to MPs asking them to back Leveson's recommendations.
About 2,000 editors will sign up to a new independent press watchdog, the chairman of the Press Complaints Commission has said.
The Prime Minister has taken a political gamble by holding differing views to the victims, the Leveson inquiry and a majority of MPs.