The Hacked Off campaign, which represents many victims of newspaper intrusion, said Lord Justice Leveson had given the Prime Minister a "workable, proportionate, reasonable solution" to the problems of press abuse.
But the group added that David Cameron "had not done his job" by failing to accept the full recommendations of the report and was wrong to trust Editors to "behave themselves".
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It will be a cloudy and at times damp morning across much of the UK, apart from the far west where it will be dry and bright.
Barack Obama has returned to the political spotlight, campaigning for Democratic candidates ahead of upcoming elections.
The prime minister said there was a "clear and urgent imperative" to give new impetus to stalled negotiations.