Matthew Dancona

Gordon Brown is finished. I said so on Newsnight last night and I say it again now with even more conviction. In James Purnell, he has lost a truly formidable Cabinet colleague, the best and the brightest of his generation, and one of the few senior Labour figures to grasp the full extent and novelty of the Cameron revival - much more than the neo-Blairite as which he is often caricatured in media profiles. Purnell also has the countenance and personality of a future leader - as the Spectator tipped last year. I hope he reconsiders his statement that he will not run in the leadership election which must surely follow before long. Number Ten will surely brief that Purnell was weighed down by difficulties over his expenses, or deranged, or both. It won't matter.

In every crisis of leadership, there are a few protagonists who matter much more than most: self-evidently, the Prime Minister’s spouse and core advisers, but also the holders of the great offices of state. The Home Secretary, Jacqui Smith, has already announced her departure, triggering today’s spectacularly ill-timed mayhem. As James pointed out earlier, Peter Mandelson handed the black spot to Alistair Darling in a BBC interview today and Gordon Brown conspicuously declined to use the future tense in his encomium of his Chancellor at PMQs. All seems to be in order for a new boss at the Treasury to be appointed in the forthcoming reshuffle and there is ever more frenzied speculation that Ed Balls is the PM’s candidate-of-choice.

The expenses scandal just keeps getting better and better for David Cameron. No, you read that right. The departure of Andrew Mackay is indeed a grievous loss to the Tory leader's inner circle and - self-evidently - a grotesque embarrassment. But, by pre-empting press disclosure, it shows that Mr Cameron will not wait for the media to force him into action. It also shows that he is willing to put the public interest before his own narrow personal interest as a party leader in desperate need of accurate intelligence on the Commons from a trusted source. It shows that Dave has the ruthlessness to govern for the nation rather than for the club. Contrast Gordon.

Leave aside the specifics: when David Cameron walks into Number Ten, his press conference this afternoon should be remembered as one of the non-electoral milestones on the road from Opposition to power. Compare and contrast the image of Gordon being interviewed on a train when the Telegraph story first broke last week – blaming the System and congratulating himself on the action he would be taking in the future to reform it. In his body language, tone and recognition of the public’s fury, Cameron showed that his antennae are much more sensitive to the electoral mood than Brown’s.

Gordon’s “Sorry” looks and sounds like catch-up – for the good reason that this is precisely what it is. In my Sunday Telegraph column yesterday, I argued that the British polity had slipped backwards on the moral evolutionary path from a “guilt culture” (governed by moral conscience) to a “shame culture” (governed only by fear of discovery) – if you are interested in this all-important distinction, by the way, try Ruth Benedict’s classic work of anthropology, The Chrysanthemum and the Sword. Only disclosure, or the threat of disclosure, has forced our parliamentarians to promise reform. I am not saying that their forbears were all paragons of individual ethical conduct.

Bits of plaster are already falling off the ceiling over tomorrow's cover story in the magazine, in which (amongst other things) I reveal a plan to launch a leadership challenge to Gordon Brown if Labour's performance in the local and European elections is as terrible as the party's strategists fear. The idea, as I explain, is for a former Cabinet minister - "probably Charles Clarke" - to test the water and see if he can secure 30 or so signatures from Labour MPs. The plotters are understandably uncertain of their chances and fear (as I make clear) that such a dramatic intervention might be counter-productive, as indeed it might. Nothing is certain, as I say in the piece. But there is absolutely no doubt that such ideas are being actively discussed by senior Labour figures.

The 50p tax bombshell is not only a reversion to the worst politics of envy - a form of politics one hoped, naively as it turned out, had been consigned to the dustbin of history. It is also the worst manifestation yet of a very modern aspect of Brownite Labour. As I wrote in the Sunday Telegraph at the weekend, Damian McBride's vile emails sent from a Government address and the heavyhanded arrest of Damian Green both reflect a dangerous belief that the public interest and party political interest are identical, co-terminous. Last night, Labour insiders made little attempt to pretend that the logic behind the 50p tax was fiscal: they know full well that it will raise next to nothing.

Hat tip for political prophecy to Michael Gove who, in October 2007, provided the best analysis of what makes Gordon tick yet delivered by a senior Tory, and one which is even more impressive in the light of the McBride Affair  In a speech to the Bow Group, Gove dissected the (then newish) PM’s flaws to devastating effect, comparing Brown’s shortcomings to those of leaders past such as Lloyd George, LBJ and Mitterrand. Idealism, sincere initially, falls victim to the methods used to win and retain power: "...in order to win power, in order to hold it, in order to manage affairs, in order to woo public opinion, that idealism is progressively diluted, twisted or sacrificed.

Yesterday, as the McBride resignation story raged, a distinguished former Labour minister asked me a rhetorical question: why is it always the same faces coming back? Derek Draper, Damian McBride, Peter Mandelson, Alastair Campbell, Charlie Whelan: all have supposedly resigned, disappeared from the front line, retired to explore new careers - and yet, here we are, in 2009, a decade and a half after Tony Blair became leader of the Labour Party and the faces remain the same. In this line-up, McBride, who only became a political adviser officially after the 2005 election, is very much the new boy. The answer is to be found, like so much wisdom, in the Blues Brothers: it is the politician's instinct always to "get the band back together again".