I cannot bring myself to listen to the audioversion of the Telegraph’s stitch-up of Vince Cable, any more than I will bother to watch his ‘celebrity’ appearance on Strictly Come Dancing. The first is too cruel, the second too silly, especially in light of the changed ‘aura’ surrounding Vince as a result of the first.

Before anyone shouts that I’m just jealous because Strictly have never asked me, they have, several times, but there is a little word called ‘credibility’ eating away at the back of my mind whenever I get these invites.

And before anyone says well Anne Widdecombe did allright, I only agree up to a point. She made herself more popular and she seemed more human in agreeing to be a laughing stock, but any remaining capital of political credibility has pretty much gone. If she doesn’t mind, fine, but once the tinsel has blown away, I think she will have her moments wondering whether it was all terribly wise.

Now Vince could have got away with it as a one off, which indeed it is, and if he were still the Saint Vince of Opposition days. He could just about have got off with it even in government, even as he was helping push through all the Tory cuts, had it not been for his latest unfortunate escapade that I cannot bring myself to listen to.

Reading it is embarrassing enough. It is not simply the fact that it catches him saying one thing in public and another in what he believes to be conditions of privacy (… someone should tell him that once you reach a certain level in politics, it is wise to assume encounters with complete strangers are ‘on the record.’) What is toe-curling is the boastfulness of it all, the idea that one word of protest and a storm-out from Cabinet would bring the whole government down … Michael Heseltine tried that and he was an altogether bigger beast back then than ex-Saint Vince is now.

It is also dreadfully weakening of him. And yet again, a mishap has taken place that plays to David Cameron’s advantage. They say lucky generals make their own luck, but Cameron has a fair few lieutenants who inadvertently help him.

Stand by for both Cameron and Nick Clegg looking a little more pleased with themselves at their joint press conference today, as they celebrate their little gift labelled ‘Happy Christmas, from silly Vince.’ The only real difficulty for Cameron is the suggestion that he wants to scrap winter fuel payments. I suspect the memo to Danny Alexander saying they need a Plan B on that one has already been sent.

And as Vince waltzes round the Strictly Come Dancing floor, many watching will think it is nice that a senior politician can dance like that and doesn’t mind sharing a bit of Christmas cheer. And Cameron will think that one of his potential problems in Cabinet has just gone and undermined himself once more. Once people start imagining they have nuclear weapons riding around in their briefcase, you begin to wonder if power has gone a little to their heads.