Leading article: Some hard questions for a press baron to answer

Next Tuesday's session will be the beginning of the reckoning over phone hacking

Rupert Murdoch has experienced more reversals in the past week than he has, hitherto, in his entire career. The latest U-turn came with News Corp's confirmation yesterday afternoon that both the tycoon and his son James will, after all, give evidence before the House of Commons culture, media and sports committee next Tuesday on the phone-hacking affair.

The pair had initially responded to an invitation from the committee chairman, John Whittingdale, to appear by saying that they were both "unavailable". But when it became clear that such imperiousness would probably land them in contempt of Parliament, the Murdochs discovered that they did have space in their crowded diaries after all.

Now attention turns to the session itself. The Murdochs have a great many questions to answer. Senior executives at News International, the UK arm of the Murdoch media empire, misled both the public and Parliament with their assertions that phone hacking was the work of a single rogue reporter. Even News International now admits this claim to have been untrue. Senior officials in the Metropolitan Police this week accused News International of frustrating their investigations into phone hacking. The chairman of the Press Complaints Commission, Baroness Buscombe, says that News International lied to her when she conducted her own investigation into the business. Mr Murdoch needs to explain how this pattern of behaviour makes his company a "fit and proper" owner of 37 per cent of the British newspaper industry.

There are specific questions of detail too. David Cameron claims that he was given a personal assurance by the media tycoon that it was safe for him to hire the former News of the World editor, Andy Coulson, as his Downing Street communications chief. Is that Mr Murdoch's recollection of events? And, if so, on what grounds did he offer such a guarantee?

James Murdoch has some important questions too. The chairman of News International implied last week that he was misled by colleagues when, in 2008, he personally authorised substantial out-of-court settlements to victims of phone hacking by the News of the World. But who were these colleagues who kept their chairman in the dark? And are they still in their jobs? The younger Murdoch must also be asked when he became aware of the existence of an internal News International dossier, apparently compiled in 2007, that indicated that phone hacking went wider than the actions of a single reporter.

Rebekah Brooks, the present chief executive officer of News International, will also appear before the committee. She needs to be probed on the evidence she gave to the committee in 2003 when she admitted that her organisation had paid police officers for information. When did Ms Brooks discover the existence of that 2007 dossier? And what did she know about the activities of private investigators contracted by the News of the World when she was editor of that newspaper?

Next Tuesday's session will be the beginning of the public reckoning over phone hacking. It will also be an important moment in the life of our democracy, with a mighty press baron forced to account for himself before Parliament. The MPs on the committee must rise to the occasion.