Q&A: The Key Questions Facing The Murdochs

Here are key questions surrounding the appearance of Rupert and James Murdoch at the Leveson Inquiry this week.

Why have they been called to give evidence?

The inquiry was set up in the wake of phone hacking allegations at the News Of The World which led to the closure of the 168-year-old News International-published paper, owned by Rupert Murdoch's News Corp.

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The 81-year-old and his son James, who was chairman of NI at the time the allegations surfaced, are expected to face further questions about the phone-hacking scandal.

Core participants - including News International - have been called because they have links or possible links to matters raised in the inquiry, or because they could face criticism as a result of the inquiry.

What might they be asked?

James Murdoch has been questioned about when he learned about evidence that suggested hacking was rife at the Sunday tabloid.

Two News of the World executives have claimed they warned him in June 2008 that the practice extended beyond royal editor Clive Goodman, who was jailed in January 2007.

Mr Murdoch's father is expected to be asked in general about his oversight of UK newspapers.

He is likely to be asked whether he exerted undue influence over British public life through his papers and his regular meetings with top politicians.

He has previously said he met David Cameron "within days" of the 2010 general election and was invited to Downing Street by Gordon Brown "many times". Tony Blair is godfather to one of his children.

Haven't they been questioned publicly before?

This week sees the pair's most high-profile appearance since they were questioned side-by-side at the Commons Culture, Media and Sport Committee last July.

However, the setting is more formal this time - both have to swear an oath promising to tell "the truth, the whole truth and nothing but the truth". And are being scrutinised not by MPs but by experienced counsel to the Leveson Inquiry, Robert Jay QC.

The fact that they are appearing separately will mean that James Murdoch will not be able to interrupt to assist his father in answering questions, as he did in front of MPs.

What does the Leveson Inquiry aim to achieve?

As well as phone hacking, its remit is also looking at the culture, practices and ethics of the press and will make recommendations for the future regulation of British newspapers.

It has already taken evidence on unethical and possibly illegal behaviour by journalists, and on relations between police and newspapers.

Inquiry chairman Lord Justice Leveson is now turning to contacts between politicians and the national press.