Leading article: A question mark now hangs over David Cameron's judgement

David Cameron sought a tone of contrition in his dramatic press conference on phone hacking yesterday.

But amidst the expressions of personal responsibility there was also a subtle attempt from the Prime Minister to spread the blame. "We have all been in this together", said Mr Cameron, as he painted a picture of an entire generation of politicians who had got too close to the mighty media empire of Rupert Murdoch.

It is certainly true that previous occupants of Downing Street, including Tony Blair and Gordon Brown, were desperate to win the tycoon's backing and that they did many undignified and dubious things to try to secure it. But this cannot disguise the fact that Mr Cameron was "in this" with the Murdoch regime, in an especially serious way thanks, in particular, to his employment of Andy Coulson, the News of the World editor who resigned in 2007 after one of his journalists was sent to jail for phone hacking. It is of course, the phone hacking affair that exploded, once again, this week with such spectacular consequences.

Mr Cameron trotted out his usual line yesterday that he magnanimously decided to give Mr Coulson a "second chance" when he made him the Conservative Party's communications chief in 2007. Those who err deserve a second chance only when they have owned up to their original misdemeanour. There was widespread scepticism in 2007 over Mr Coulson's claims that he was unaware phone hacking was taking place on his watch. How scrupulously did the Conservative leader challenge Mr Coulson's assurances on this subject? Was Mr Coulson asked about any other potential embarrassments that could emerge from his past? No adequate answers to these questions were provided by the Prime Minister yesterday.

Mr Cameron implied that he could not have been expected to foresee what a disaster the Coulson appointment would become. This is disingenuous. The Prime Minister was warned, both in public and in private, not to take a compromised figure like Mr Coulson with him across the Downing Street threshold. Yet the Prime Minister chose to ignore those warnings. And, as head of communications, Mr Coulson was installed close to the very centre of the Government machine. All this inevitably raises serious questions about Mr Cameron's judgement. And so does the Prime Minister's remarkable description of Mr Coulson as "a friend" yesterday, even as the former editor was about to be arrested.

There are further problems with Mr Cameron's attempt to present the appeasement of the Murdoch press as something for which all politicians are equally guilty. While his predecessors were, at various time, close to the Murdoch regime, Mr Cameron was singularly enthusiastic about cultivating the media group. The Prime Minister declared yesterday that if he had been in a position to receive the offer of resignation of the News International chief executive, Rebekah Brooks, he would have accepted it. Yet not long ago Mr Cameron was apparently a close personal friend of Ms Brooks. The pair are said to have gone riding together. Mr Cameron attended a dinner party at Ms Brooks' Oxfordshire home over Christmas, a party at which the senior News Corp executive James Murdoch was also present. And this was at a time when the Government was considering the media company's controverisal bid to acquire the broadcaster BSkyB.

Worse, Mr Cameron's Government appears to have granted special favours to the Murdoch organisation. In January, Ofcom recommended that the BSkyB bid should be referred to the Competition Commission. But the Culture Secretary, Jeremy Hunt, decided to allow the company to avoid this referral in return for an agreement to sell off Sky News. It is inconceivable that any other organisation would have been offered such regulatory leeway.

Mr Cameron is right to argue that a great many politicians, from Labour as well as the Conservatives, must account for the manner in which they have bent their knee to the power of the Murdoch media. But the Prime Minister should be in no doubt: it is he who has the most explaining to do.