Guido Fawkes summoned to press inquiry after leak

Blogger publishes 'evidence' from Alastair Campbell ahead of his testimony

Paul Staines, the right-wing political blogger known as Guido Fawkes, was last night summoned to appear at the Leveson Inquiry after a document purporting to contain evidence from Alastair Campbell was leaked online.

Calls were growing for an investigation into how an alleged draft of evidence from Tony Blair's former spokesperson appeared on Guido Fawkes's website. The breach prompted an instant rescheduling of the inquiry with the official version of Mr Campbell's testimony now set to be published today – a day earlier than planned. Lord Justice Leveson is also expected to make a statement on the new arrangements, while Mr Campbell will appear in front of the inquiry on Wednesday.

Sources have told The Independent that the document is not the final version of what is to be officially posted online but it has nonetheless provoked an angry response among panel members who have called for an investigation and are threatening legal action.

The document contained numerous references to Mr Campbell's time in government, charting the fractious relationship that the Blair administration had with some of the tabloids. Some of the most probing questions involved the Blairs' relationship with the Daily Mirror ahead of Cherie Blair's pregnancy. The document questions how the newspaper was able to break the news of the pregnancy in 2002. "I do not know if her [Carole Caplin's] phone was hacked, of if Cherie's was, but, knowing what we do now ... I think it is at least possible this is how the stories got out," it said. The document alleges that Mr Campbell was the recipient of "threatening text and phone messages" from the then-chief executive of News International Rebekah Wade and the office of James Murdoch.

A statement issued by Lord Leveson last night said it "was extremely concerned to hear that a copy of the evidence Mr Campbell intended to provide to the inquiry was published on the Guido Fawkes website.

"The website asserts that this statement was obtained by legal means but Lord Leveson will be inquiring further into this claim and Paul Staines will be required to give evidence." Mr Campbell said he was "genuinely shocked" to see his evidence in the public domain.

Leveson: this week's appearances

Charlotte Church and the broadcaster Anne Diamond will give evidence today as Lord Justice Leveson continues his examination into media ethics. The retired teacher Christopher Jefferies, who was vilified in the tabloid press after being wrongly arrested on suspicion of the murder of Joanna Yeates, will also appear.

This week Lord Leveson will expand the scope of his hearings beyond victims of press intrusion to people who have worked in and closely with newspapers. On Tuesday, The Guardian journalist Nick Davies, who wrote about the scale of the News of the World phone-hacking scandal, the former Daily Star journalist Richard Peppiatt and the ex-News of the World deputy features editor Paul McMullan are expected to give evidence.

Terri Judd