There is a little vignette in the first volume of Alastair Campbell’s diaries that makes it abundantly clear that, at the time, we were being governed by people who were mentally ill. It is yet another furious, bitter, gut-churning row involving Campbell, Tony Blair and Peter Mandelson and concludes with Mandelson stamping his little feet and screaming: ‘I am sick of being rubbished and undermined! I hate it! And I want out.’ The cause of this dispute was not whether or not Labour should nationalise the top 200 companies and secure for the workers by hand or by brain the full fruits of their industry. Don’t be silly. It was about whether Blair should wear a suit and tie to deliver a speech or if, instead, he should put on a nice pair of cords. Mandelson was in favour of the cords, by the way.

It is impossible to read this sort of thing without coming to the conclusion that the most senior elements of New Labour were mad as hatters, candidates for a longish stay in the booby-hatch. I do not mean mad-eccentric, as in the manner of some Ukip councillor who thinks women should be exterminated or something. I mean seriously damaged, deeply troubled people. If you read on through those diaries, this view is amply confirmed: these awful, awful people who are perpetually wracked with a paranoid fury, drunk or constipated or hunched over the toilet bowl with their fingers down their throats or visited by the Black Dog of depression, or ulcerated or prostate on some sofa to banish the clamorous headaches. And of course continually lying to one another when they weren’t lying to the rest of us, continually stitching each other up, dissolving in a vat of their own bile.

There have been plenty of diaries emanating from the rule of New Labour (and its hilariously incompetent vestigial tail presided over by the maddest of them all, Gordon Brown) by various unelected and now dispossessed political munchkins, most of them expressing a commercially expedient contrition along with the grotesque outrages, the infractions of democracy, the utter contempt not just for the electorate but also for most of their elected MPs.

The latest comes from a saturnine pudding-faced thug called Damian McBride, who worked as a hatchet man for the greatest man on earth (in McBride’s somewhat contentious view), Gordon Brown. This oaf’s revelations are being serialised in a morning newspaper, all the usual toxic leaks designed to destroy his comrades’ careers, and  the usual emetic hands-up-guv-I-shuddna-dunnit faux apology. McBride, who was finally kicked out of his job for inventing filth about various high-profile Conservative politicians is not really apologetic, of course. Far from it; he simply wishes to sell his book and knows that in order to do so it must be seen as a confession rather than an elongated boast. The extent of his contrition can be gauged from the timing of publication — first day of the Labour conference, thus designed to wreak maximum havoc on the party of which he was, and possibly still is, a member. Just like the stuff he used to do for Gordon, in other words. And also, lest it should be in doubt, his defensiveness when held to account by some of those he undermined, such as the shadow foreign secretary Douglas Alexander. McBride is no more sorry than is Alastair Campbell; like Alastair, he just wishes to trouser as much dosh as is humanly possible from his tawdry revelations.

I suppose the political correspondents will tell you that the source of that paranoid fury on both sides, Blair and Brown, was the deal or no deal which took place between the two at the Granita restaurant in Islington. From that, all manner of madness sprang. Blair’s disingenuous promise, Brown’s lowering, semi-restrained fury. But I think this is probably putting the cart before the horse. My guess is that long before that dinner each was, as the Americans put it, crazier that a shithouse rat.

A megalomaniac on one side, a paranoiac devoid of even the most primitive vestiges of human sociability on the other. Tony Blair retreating upstairs at key moments to talk to God, and no doubt telling Him, in an affable manner, just where He was going wrong, is but one example of what I would call certifiable behaviour. Not certifiable because Blair believed in God, but because of the nature of his relationship with God, whom our Prime Minister seemed to treat as he would a low- to middle- ranking cabinet minister. Keith Hill, say, or at best Frank Dobson.

And on both sides the loathing — of their own colleagues, of the press, of the electorate. Campbell describes the late Philip Gould, party strategist, as wishing to ‘punch’ members of a focus group when they deigned to disagree with official party policy. Campbell is on record as describing the entire electorate as ‘not serious people’ when they, too, showed signs of not being on message. This messianic aloofness from the real world was bound, in the end, to turn all the participants doolally, so perhaps we should not be too hard on Mr McBride. But has there ever been an administration in British history where everyone hated one another so much? I think you’d have to go back to Edward IV.