Leading article: Conclusive evidence of the cosy club at the top

After two days of evidence from Andy Coulson and Rebekah Brooks at the Leveson inquiry, there can no longer be any doubt of the inappropriate proximity of the political classes and News International. From the friendships, to the text messages, to the social dinners at which matters of high politics and high business were discussed; the picture painted is of a world where the lines between the professional and the personal are altogether blurred.

There is, of course, always going to be contact between politicians and the media. And so there should be. It is right that journalists be fully informed, and much is gained from less formal discussion. But the testimony from the former editors of the News of the World and The Sun points to something else entirely.

Ms Brooks may claim to be confident that, whatever the relationship, she never forgot she was a journalist and they never forgot they were politicians. It is a reasonable assertion, but one that is difficult to square with either once-weekly text messages from David Cameron – then leader of the Opposition – commonly signed off "lol" (by which he meant "lots of love") – or her attendance at his private birthday party after he became Prime Minister. Neither was such familiarity specific to Mr Cameron. Tony Blair was "a constant presence" in Ms Brooks's life while she was a newspaper editor, and she was good friends with Gordon Brown's wife Sarah, although her relationship with Mr Brown himself soured. Over a period of 10 years or more, Ms Brooks was at the centre of a web that went far beyond the purely professional contacts of a senior journalist.

With a criminal investigation into phone hacking underway, many important questions could not be asked. But there were still two other substantive developments at Leveson this week. The first was the admission that, at a private dinner with George Osborne, their respective spouses and another couple in late 2010, Ms Brooks and the Chancellor discussed News Corp's highly controversial bid for BSkyB.

Ms Brooks claims the conversation was very short and "not inappropriate", that it was merely her attempt to counter the virulent opposition to which Mr Osborne had been widely exposed. Perhaps it was. But that does not matter. The issue is that there was the possibility of any such conversation at all. Much of Ms Brooks' testimony hinged on her assertion of personal integrity, on her claim always to know where her responsibility lay. One need not question that integrity, however, to suggest that even the opportunity for corruption should never arise. And that is to say nothing of the questions that Mr Osborne must now answer.

Second, and more explosive still, was the publication of another damning email from Fréd Michel. Not only does the News Corp lobbyist appear to set out in detail what the Culture Secretary will tell Parliament about the BSkyB takeover a few days later. He also claims that Jeremy Hunt is resisting calls for a public inquiry into phone hacking, and is requesting private advice from Mr Michel "to guide his and No 10's positioning" on the scandal.

When the wholly improper contact between Mr Hunt's office and News Corp first came to light last month, it was only the overt – and indefensible – backing of a Prime Minister desperate to protect himself that kept Mr Hunt in his job. No doubt the Culture Secretary will now replay the same excuses: that Mr Michel was overplaying his hand and that his own evidence to Lord Justice Leveson later this month will prove his integrity. It is not enough. Mr Hunt cannot cling on any longer. He must resign. And the uncomfortable revelations from the Leveson inquiry must continue until the Augean stables are finally swept clean.