Conservative Prime Minister David Cameron is due to appear at the Leveson Inquiry on Thursday, in a week of intense scrutiny of the ties between both of Britain's main political parties and Murdoch's News Corporation empire.

Brown, Labour prime minister between 2007 and 2010, was asked in early questioning about a story printed by the Murdoch-owned Sun in 2006 which revealed that his son had been diagnosed with cystic fibrosis.

He said he "absolutely" denied that his wife gave consent for the story to be published, contradicting claims by Rebekah Brooks, the tabloid's editor at the time, when she gave evidence to the Leveson Inquiry last month.

Brown was also set to face questions about his relationship with 81-year-old Murdoch, after the Australian-born tycoon told the inquiry that they enjoyed a "warm personal relationship".

Osborne was also expected to face challenging questions over his government's links to the tycoon after the Conservative-led coalition government came under fire over revelations about its closeness to the Murdoch press.

Culture minister Jeremy Hunt has been battling calls to resign since it emerged at the inquiry in April that his office leaked information to News Corp. about its bid to take full control of pay-TV giant BSkyB.

Cameron, who is due to give a full six-and-a-half-hour day of testimony on Thursday, launched the press ethics inquiry last July in the wake of the phone-hacking scandal at the now-defunct News of the World.

The tabloid was forced to close after revelations that it hacked into the voicemail messages of a murdered teenage girl, as well as dozens of public figures, sparked a wave of public revulsion.

The inquiry, led by Judge Brian Leveson, is due to produce a report in October that will likely include recommendations on the future of press regulation and a probe into the extent of journalists' illegal activities.

More than 40 people have been arrested by police investigating phone hacking and alleged bribery of public officials by News Corporation journalists.