The possibility that Mr Murdoch's market dominance, through News International, will survive untouched is certain to be greeted with dismay and anger by Labour's rank and file. However, senior party figures believe that forcing him to sell some of his titles would raise too many practical problems.
News International controls the Times, the Sunday Times, the Sun, Today, the News of the World, BSkyB and Harper-Collins, the publishers, while Mr Murdoch owns 66 per cent of daily newspapers in state capitals in his native Australia.
The group and three others, Associated Newspapers, Mirror Group and United Newspapers, account for 85 per cent of national daily papers.
But well-placed sources within the Labour Party say it would be too problematic to impose a regulatory system that smacked of retrospectivity because it forced the sale of existing titles.
One senior front-bencher said: "There would be practical problems in finding buyers. There would be no ready purchaser, for instance, for Today. It would not be possible for Labour to order Murdoch to divest himself of any of his titles."
It is understood that the stance has the backing of Chris Smith, shadow national heritage secretary, and it is expected to be endorsed by Tony Blair, the Labour leader.