Here are the facts: we now know David Cameron is a pretty close friend of News International's former chief executive Rebecca Brookes.

We know this in some detail – from his rides on her ex-police horse to the frequent texts, with their clumsy acronym usage.

We know there were other significant contacts between Rupert Murdoch's News Corp and the Conservative Party under Mr Cameron, not least the security-light hiring of Andy Coulson as the soon-to-be Prime Minister's PR man.

We now know that at the time Jeremy Hunt was given responsibility for ruling on News Corp's bid for control of BSkyB, he had already written a memo to Mr Cameron insisting it would be totally wrong to "cave in" to the deal's opponents, the UK could "lead the way" if the takeover was allowed, and that the UK's media sector would "suffer for years" if it was not.

And we know Vince Cable was relieved of responsibility for deciding on the same bid because it emerged his personal view was plainly biased against Mr Murdoch's empire.

It is evident both decisions cannot be correct. If it was right to alleviate Mr Cable of the quasi-judicial duty due to him having formed a preconceived idea of the desirability of a Murdoch takeover at BSkyB then it cannot have been correct to hand the task to the Culture Secretary who had formed equally fixed ideas but in the opposite direction.

No amount of bluster over Mr Hunt having sought independent advice at every stage – as Mr Cameron insisted yesterday – can change that.

Of course other politicians and parties have had their links with News Corp: Tony Blair became godfather to one of Rupert Murdoch's daughters. But in Mr Blair's case the links did not spill over into influencing one of the most important political and commercial deals for decades.

Any reasonable person would conclude instead that there was something malodorous about the decision and that it suited Mr Cameron to appoint someone who was biased not against the bid, but in favour of it – in order to advance the interests of some of his friends in the media industry, and enhance the prospects of the Conservative Party.

This is the analysis Mr Cameron is keen to discourage. "There was no great conspiracy," he claims.

Will that wash in the court of public opinion? Revelations from the Leveson Inquiry are now heaping pressure on the Prime Minister, and the time may come when he too faces calls to resign over the tangled relationships between the Murdoch empire and the Conservative half of the Coalition Government.

Ultimately, it is a matter of judgment. Politicians can bring a number of skills to the job. But the one thing they must have is judgment, and Mr Cameron's is now seriously in question.