Leading article: The Prime Minister has questions to answer, too

From the testimony of News Corp's top lobbyist to the Leveson Inquiry yesterday it is clearer than ever that Jeremy Hunt cannot defend his position in the Government. And the whiff of impropriety attached to his supposedly impartial review of the Murdochs' bid for BSkyB is drifting closer to the Prime Minister by the day.

First, Mr Hunt. Fréd Michel denied that the contact between him and Mr Hunt's office over the highly controversial deal was inappropriate. He also denied that their communications constituted a "back channel". Most important of all, he refused to admit that the weight of evidence – drawn from a welter of emails and text messages – suggested that the Secretary of State's views were tilted News Corp's way. But he hardly needed to.

Although Mr Hunt excused himself from direct contact with the company when he took over quasi-judicial oversight of the bid, the volume of contact between Mr Michel and Adam Smith – the special adviser who resigned when the scandal broke last month – was truly staggering. In only slightly more than a year, both before and after Mr Hunt became the arbiter of the deal, nearly 200 phone calls, more than 150 emails and in excess of 1,000 text messages passed between News Corp and the Department, the vast majority of them between Mr Michel and Mr Smith. On so complex an issue, some contact is to be expected. But this is something else entirely, including requests for opponents' documents, early steers on ministerial thinking and advice on how to tackle the recalcitrant regulator. No amount of bluster and buck-passing from Mr Hunt can hope to answer the questions raised.

The Culture Secretary and his supporters still hope to discredit Mr Michel with the claim that his reports to his superiors were largely the puff and posturing of the public relations professional. Mr Smith's testimony to the inquiry – the bulk of which will be today – will no doubt dispute Mr Michel's repeated assertions yesterday that he would not have mentioned issues to his News Corp bosses that had not been discussed with Mr Hunt's office. The back-and-forth of who said what, and what they meant, matters little, however. The principle is enough.

Mr Michel did his job well, pushing as hard as he could on all available doors. It was up to the Department to push back as necessary, and it manifestly failed to do so. Neither is it sufficient to claim that Mr Smith went beyond his brief. The deal on the table was set to re-shape Britain's media landscape, and it came against the backdrop of the growing investigation into phone hacking. Either Mr Hunt was complicit in his subordinate's excesses, or he was catastrophically dilatory in his management. Regardless of which it was, he is not fit for office.

But the Culture Secretary is no longer the only one under fire. David Cameron is also increasingly exposed. An email from the Culture Secretary to the Prime Minister revealed at the Leveson Inquiry yesterday makes unmistakeably clear Mr Hunt's support for News Corp's proposal. Sent just a month before Vince Cable was revealed by a newspaper sting to be parti pris, the email cannot but spark accusations that one cabinet minister deemed to take the wrong line was replaced by one with more acceptable views. Indeed, at the very least it suggests the Prime Minister was not paying much attention, despite the far-reaching implications of the decision to be made.

Thus far, Mr Cameron has protected his Culture Secretary, in an attempt to shield himself from the fallout of so high profile a departure. Always an unedifying spectacle, such manoeuvrings are no longer viable. Mr Hunt must go. And Mr Cameron must explain why he was considered appropriate to take on the BSkyB bid in the first place.