In just one interview, Cameron lost the only thing he had going for him

Gordon Brown at his lunatic worst would not have done this

David Cameron has said he does not wish to serve a third term (Getty)

In the annals of outlandish excuses, few have rivalled the one offered on Monday for the shock revelation with which David Cameron exploded his central re-election message, uttered from the kitchen (where else? why they bother with the situation room any more is beyond me) of his Oxfordshire home.

All respect to Alex Ferguson for blaming a Manchester United defeat on his players’ inability to recognise each other in unfamiliar grey shirts, and to Mark Oaten for sourcing a bath time dalliance with a rent boy to mid-life angst occasioned by hair loss. But these and other classics have been relegated to mundanity by the attempt at damage limitation from Downing Street.

Asked what the PM had in mind when he spoke them things what he said – forgive the Glenn Hoddle allusion, but in the crazy circus it feels apt – about not standing for a third term, an unnamed Tory aide said this. “It’s not part of any great scheme. He was chopping carrots at the time.”

The Food Prepping Distraction Defence seems wholly original, though you can’t be categorical about that. It was rumoured, in 1945, that a White House spokesman briefed reporters not to read any military intent into Truman’s order to drop the atomic bomb on Hiroshima “as the President was blanching a turbot at the time”. On balance, however, this seems unlikely, and in the hours since the broadcast many have tried to explain away what was less an average unforced error than Novak Djokovic chasing a lob that would have landed 15 feet over the baseline, and smashing the ball into his mouth.

The current Conservative line to take, as parroted by the Defence Secretary Michael Fallon, is that Cameron is our very own Honest Abe, or George Washington, and can do nothing but tell the truth. Boris Johnson, one of three pretenders to his throne mentioned by Cameron, though still sadly riven by lack of ambition, cast doubt on that by insisting that the next party leader is “a babe unborn”. Either Boris doubts his PM’s word, or the rumbling row about breastfeeding in the Commons is about to take a startling turn.

In a delectably wry Newsnight appearance, meanwhile, Michael Gove made a pig’s ear out of a pig’s ear when cross-examined by the bemused tag team of presenter Evan Davis and Alastair Campbell. With people tired of spin, said Govey in a subtle dig at Ali and his former boss, we are in “a brave new world” where the Prime Minister gives straight answers to straight questions, and we’d jolly well better get used to that.

Anyone seduced by this utopian vision was soon disabused. When Davis repeatedly asked Govey when and how Cameron, having pledged to serve every day of a five-year term, would hand over to a successor before the 2020 election, the only straight answer would have been: “Beats the hell out of me. I’m only here because they couldn’t find anyone else to come on and pretend like this isn’t the most doolally political cock-up since … well, if I’m candid, Evan, ever!”

So it is. Gordon Brown at his lunatic worst would not have done this. In one brief exchange, possibly chillaxed to destruction because his Eton contemporary James Landale of the BBC is so absolutely PLU (People Like Us), the PM did worse than jettison his central campaign message of solid stability, and replace it with the promise of ceaseless internecine warfare between the challengers he named.

He also savagely undermined what had been his USP. Cameron has also been hopeless at the politics. After needlessly offering up the Union and almost losing it, his monstrously cynical mishandling of the referendum’s immediate aftermath ensured Scottish independence soon enough.

With alarming impetuosity, he tried to bounce Parliament into an inevitably counter-productive bombing campaign on Damascus, and was only spared disaster by Ed Miliband’s opposition. He blithely consented to George Osborne incinerating that earlier key message about economic solidarity by lowering the top rate of income tax. At the politics, as I said, he is atrocious.

The one thing he had going for him was the presentation. He knew how to do the public relations stuff – that silky projection of presidential authority. Now he chucks away not just the projection of presidential authority, but the fact of it. Of course, declaring he doesn’t want to go on for ever was, as Gove said on Newsnight, a statement of the bleedin’ obvious. But it is another statement of the bleedin’ obvious that, by specifying the precise moment he means to go – by firing the starting pistol for the succession without a moment’s thought to the method or timing of transferring power, or to the power vacuum such uncertainty must create – he committed an act of self-harm with his trusty chopping knife.

If he can no longer handle the media side of it, what’s left? What’s left, if he can form a Government after this, is an extended period of instability. It might be two-and-a- half years if, as previously expected, he goes after the 2017 EU referendum (good luck renegotiating terms with Angela Merkel as a time-limited sitting duck), or it might be the full five. Either way, the future he offers is one of in which the giant rats he thoughtfully placed in a sack – Osborne, Boris and Theresa May – bite lumps out of each other while a bunch of smaller vermin (Jeremy Hunt, Sajid Javid, Owen Patterson and so on) wait for the three of them to devour each other to death.

Five weeks of skirmishing for power is a spectator sport we all enjoy. Five months is a draining bore. Two-and-a-half years, as Mr Tony Blair’s latter period of office established, is torment. Five years of civil war would be one of those circles of hell that Dante never quite got around to writing up. If this is the carrot David Cameron dangled before us on Monday, he would have been better off jabbing the electorate in the eyeball with a sharp stick.