Its outline is buried in the draft Communications Bill published last week. The size of the potential levy on Sky, 40% owned by Murdoch's News Corporation, is unclear. But analysts speculate that Tony Blair could use the threat of a 'dish tax' to squeeze concessions from Murdoch, owner of The Sun, News of the World, The Times and The Sunday Times. Any levy could be made on users of the Sky service, or imposed on the company itself.