Tony Blair will give evidence to the Leveson Inquiry on Monday, three days before the Culture Secretary Jeremy Hunt provides testimony that is likely to decide his Cabinet future.
The first former prime minister to appear before the press standards inquiry will be asked about his relationship with newspaper groups both before and during his time in Downing Street, in particular his relationship with Rupert Murdoch and News International.
Lord Mandelson, the former business secretary, last week admitted that Mr Blair, along with other senior politicians, had become "closer than was wise" to the media mogul but denied there had been any "Faustian pact" to secure the support of The Sun.
Mr Blair, who is godfather to one of Mr Murdoch's children, can also expect questions over relationships with senior NI executives, including Rebekah Brooks, the former editor of The Sun and the News of the World. The Labour MP Tom Watson this week told Lord Justice Leveson that the Murdoch empire had tried to end his investigations into the phone-hacking scandal by asking Mr Blair to "call him off".
The appearance of the former prime minister will be the curtain-raiser to a crucial week of testimony. Mr Hunt, who has been accused of showing bias toward Mr Murdoch's News Corp during its takeover bid for BSkyB, will take the stand on Thursday. The beleaguered Culture Secretary is battling for his job following the publication of a raft of emails and texts showing a flow of privileged information from his office to News Corp and its lobbyist, Fred Michel, throughout the time Mr Hunt was supposed to be making a quasi-judicial ruling on the proposed takeover.
Other senior politicians to appear before the judge include the Education Secretary Michael Gove, a former senior editor on The Times, who said the inquiry was creating a "chilling atmosphere" towards freedom of expression.