Rupert Murdoch called Tony Blair urging him not to delay the invasion of Iraq, former Number 10 communications chief Alastair Campbell has said.
The claim is made in the latest part of Mr Campbell’s diaries, which are being serialised in the Guardian newspaper.
Mr Campbell said there were three calls in March 2003, a week before a crucial vote on Iraq in the House of Commons.
Mr Murdoch’s company, News Corporation, said claims he lobbied Mr Blair were “complete rubbish” and unsubstantiated.
The media boss previously told the Leveson inquiry he “never asked a prime minister for anything”.
There has been no response to the claims from Mr Blair’s office.