Why has Andy Coulson resigned now, after clinging on so long, and just days after David Cameron backed him? If his position has suddenly become untenable it is hardly just because, as he put it, the spokesman needs a spokesman. They could afford a line of 20 of those.

One of the reasons must be the simple one that the “one rogue” defence of his time at the News of the World has collapsed. The suspension of senior news executive Ian Edmondson and the naming of one other former news editor in court documents related to alleged phone hacking have left News International struggling for a form of words to shore up its position. And all the time the lawsuits from angry celebrities continue to pile up.

But you don’t have to be a conspiracy theorist to ask whether the future of BSkyB is as important in the balance of factors here as the question of how many people still believe Coulson could have failed to know members of his staff were hacking phones.

James and Rupert Murdoch are determined to buy the shares in BSkyB that they don’t already own. It is the springboard for their UK business strategy over the next ten years and compared to this the fates of Andy Coulson and a bunch of News of the World hacks probably doesn’t add up to much.

The Murdochs don’t usually care much about public opinion either, but they need political blessing for the BSkyB deal to go through. In this context the embarrassment of constant stories about hacking (even though most of the press has shabbily ignored them) is most unwelcome, and there is no doubt that Coulson’s presence at the heart of government has made that worse.

Now he’s gone, will the TV deal be easier to pull off? Only if we’re all suckers.

So bad has the phone hacking scandal become that the whole News International hierarchy has questions to answer, and that includes not only Rebekah Brooks but James Murdoch himself — for one thing, he personally approved the six-figure settlement payment to Gordon Taylor which was prompted by the discovery of that infamous bunch of hacked transcripts marked “for Neville”.

If James Murdoch wants to convince us that his company should be able to own BSkyB outright, with all the monopolistic opportunities that affords, then he needs to convince us that the company he already runs is a clean one. And before that can happen we need to see what happens to Sienna Miller, Chris Tarrant, Andy Gray, Steve Coogan and the host of others who are in the courts claiming that Murdoch’s paper breached their privacy.

Read more Brian Cathcart on Metgate here, here, here, here, here and here

Brian Cathcart teaches journalism at Kingston University London and tweets at @BrianCathcart