No one expected the final stage of the Conservative party leadership contest to be a staid and dignified affair. The Tories are now more spectacle than party, more farcical roadshow than government. But barely a week in, and it feels like events are escalating at the pace of a crammed last episode of a poorly crafted drama – the writers just want to wrap it up because they have already been told there will be no second series.

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Boris Johnson’s much anticipated interviews over the past 24 hours have been a series of how-did-we-end-up-here moments. In an interview on LBC yesterday, he petulantly refused to answer questions about an allegedly recent photo of him and his partner looking cosy after the domestic incident reported last week. “Why should I!” he sulked. The rest of the time he descended into word salads and often just sounds, a harrumphing cornered animal. In another even more alarming interview, we saw Johnson talk about his supposed model bus crafting hobby in slow motion, his eyes glazing over. It wasn’t that it had the air of something made up that was worrying, it was that he seemed to be drifting away as he was fabulating. Like a chirpy robot running out of batteries and slowing down to a drawl, Johnson’s whole demeanour during the campaign so far is that of someone who has burned himself out just before destiny called. He’s tired and irritated and can’t keep up. His shtick, the bumbling posh boy swashbuckling act, is getting so old even he is bored of it, especially when it doesn’t quite cut it when scrutiny is at full-on potential prime minister levels.

For as long as I can remember, Johnson supporters have been telling me that it’s all a clever act, that the man is an intellectual who disarms his critics in order to stealthily outwit them. Not many are saying that any more. He’s not even as good as Donald Trump; his bag of base-galvanising tricks is much sparser. Business leaders (remember when they were the Tories’ mates?) are now using code red language. Writing in the Guardian, Andrew Sentance, a former member of the Bank of England’s monetary policy committee, said “the idea that Boris Johnson will become our prime minister fills me – and many other business people – with horror”.

Johnson is now nobody without the Brexit ultras of the Conservative party membership. And he knows they will see him through, so why expend any more effort than is needed? “Why should I!” should be his campaign slogan. This all leaves Jeremy Hunt shadow-boxing an opponent who cannot be bothered and whose temperament is so frayed he now cannot handle basic debate. And so Hunt, looking a bit lost, too scared to alienate Brexiters but also needing something to actually campaign against, gestures weakly at Johnson’s evasiveness in a general “this is just not on” fashion, while posting random pictures of himself on the trail eating pizza and hashtagging his every move #hastobehunt. Inspiring stuff.

The Johnson campaign is now officially in so much trouble that it has hired Six Sigma saviours Iain Duncan Smith and Mark Fullbrook, the man behind Zac Goldsmith’s dirty yet still unsuccessful campaign against Sadiq Khan. The phrase you will hear more than any over the next few weeks is “a week is a long time in politics” as analysts hedge, still convinced that Johnson might curveball himself somehow. It’s not going to happen, despite the wheels coming off the dubious bus. Johnson and his Brexit base are playing out the endgame of the Conservative party, so long in the making. The prophecy will be fulfilled and Johnson will become prime minister. But the day he steps into No 10, when it is no longer up to the Conservative party membership, when the level of scrutiny he faces is infinitely greater than a Nick Ferrari interview on LBC, Johnson and the Tories will fall off the edge. The question then will be how much of the country will they take with them.

• Nesrine Malik is a Guardian columnist