If only it were that simple. In BorisWorld, all Boris Johnson has to do is turn up to sprinkle the stardust of mindless optimism and things fall into place. It worked for Brexit and it worked for his 2019 general election campaign. Bertie Booster ruled OK. But climate change is a rather tougher nut to crack. Other countries aren’t quite so susceptible to his charms and the Cop26 summit in Glasgow is in danger of ending in disappointment.

Quite what Johnson expected to achieve by turning up to Cop26 for a few hours on Wednesday afternoon was anyone’s guess. Still, at least he travelled by train this time. Maybe he just couldn’t accept his powerlessness and that his presence was a total waste of time. That talk of banging negotiators’ heads together really wouldn’t cut it after all. Whatever it was, there was none of the Bertie Booster tub-thumping about the 25-minute press conference he gave shortly before he scuttled back to London.

This was about as close as you’ll ever get to Johnson admitting defeat. He did go through the motions of saying “1.5 was still alive” but his body language rather suggested the opposite. His shoulders were stooped and his opening speech was delivered with little enthusiasm.

We were into the hard yards, he said. Stuck in a rolling maul in the final furlong. Our children and grandchildren would not forgive us if we didn’t agree a deal. And right now he would settle for one that he could sell as significant even if it was effectively worthless. Just to save face. What was required was more ambition and implementation. It wasn’t clear who he expected to supply them. “When are leaders going to lead?” he asked. It’s a question some of us have been asking about him for a while now.

There were a few token questions about the conference but most of the media seemed to have already made up their minds that Cop26 wasn’t going to be the gamechanger the government had tried to build it up to be before it started. Rather, they used the time to encourage the prime minister to break his omerta on Tory sleaze. For the last week or so, Bertie Booster has been uncharacteristically quiet.

It soon became clear why. Because Johnson was about to rewrite history to suit himself. Even for such an accomplished liar, this was quite something. A deception on the grandest of scales. A self-deception on the most tawdry of scales. Here was Johnson, a man incapable of honesty and bereft of self-esteem, pulling out all the stops to distance himself from the scene of the crime. This is his special talent. Because he doesn’t just always betray his family, friends and colleagues. He also always betrays himself. The self-loathing must be intense.

Boris began by saying that any MP who had been found to have broken the rules must be punished. Er … yes. Only he appeared to have totally forgotten that Owen Paterson had been found guilty of multiple egregious cases of paid advocacy. And that Johnson had imposed a three-line whip on his own MPs to get his suspension put on hold until the case had been re-examined by a new committee with a majority of well-disposed Tory members, who would now come to the right conclusion. It was about as sleazy as it gets.

Yet here was a Bertie Booster, admittedly on worn-out Duracell batteries, trying to portray himself as a champion of natural justice. Boris Johnson is going to be very angry when he catches up with Boris Johnson who fucked up so badly. He could scarcely bring himself to mention Geoffrey Cox. There again, he must be sick with envy at the amount Geoff has raked in since becoming an MP.

From there on in, it was something of a pile-on. Johnson was entirely unrepentant. Three times he was asked to apologise, and three times he said nothing. Not even an insincere expression of regret for impressions that might have been given. The Tory MPs whose second jobs have come under the microscope as a direct result of his own misjudgment might at least be hoping for a “sorry” in private. Despite all evidence to the contrary, he also declared that the UK was about as uncorrupt a country as you could find – GBP3m for a peerage, anyone? There again, he is a prime minister who once declared the GBP250k a year for his Telegraph column to be “chicken feed”, so no wonder he can’t see what all the fuss is about.

Still, Boris wasn’t finished. He then said there was nothing wrong with second jobs provided MPs put their constituents first. Something he had failed to do when he had carried on as London mayor despite being elected to Westminster in 2015. And he insisted his own behaviour was beyond reproach. It was just nobody’s business who paid for the redecoration of his Downing Street flat. Or if he accepted a free holiday from someone he put in the House of Lords. Wrongdoing must be punished, he said repeatedly. Perhaps he has a subconscious desire to be found out. One for his therapist.

None of this would have gone down well with Tories hoping to draw a line under the corruption scandal. Far from killing the story, Johnson had taken politics a step further into the sleaze bath by refusing to accept any responsibility. Par for the course for a self-destructive narcissist. He was asked why he didn’t stay up in Glasgow, even if the chances of a meaningful deal were minute. Just to show he cared. But then he doesn’t really. The only thing he really cares about is himself.

A Farewell to Calm by John Crace (Guardian Faber, GBP9.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.