It was the pathos rather than the hypocrisy that really struck home. The entertainer who used to sell out the O2 and now can’t even buy a gig as a warm-up act in front of a captive afternoon audience of retirement home residents. Boris Johnson tried all his familiar tricks. He smirked. He trotted out some bad gags. He spoke a bit of Latin. He went off on predictable riffs.

All things that had worked so well for him in the past but now fell completely flat. He was a man with only his own narcissism for company. And there’s no lonelier place than that. He coulda been a contender. He coulda been someone. Instead of the bum he now is.

This was the speech in which the foreign secretary was supposed to be making the positive case for Brexit. But like so much of what Boris does, the subtext was all about him. His need to justify his own decisions. His need to be taken seriously. His ambition. He spoke a lot about unity and bringing people together, but right at the end he couldn’t even bring himself to say he wouldn’t resign from the cabinet and launch his own leadership bid if Theresa May didn’t deliver his Brexit vision.

Play Video 2:57 Boris Johnson: Brexit is not 'a V-sign from the cliffs of Dover' - video highlights

Boris began on familiar ground. Betrayal. A subject about which he has plenty of first-hand knowledge, as there’s scarcely a member of his own family, let alone his friends and colleagues, whom he hasn’t betrayed at some time. Just about the only thing he hasn’t betrayed are his principles. And that only because he doesn’t really have any. Principles are like mayflies for Boris. Here today, gone tomorrow.

It would be a huge betrayal if the government didn’t deliver on the one true Brexit. Which may have been rather different from the Brexit he had peddled during the referendum campaign, but that was then and this was now. So all those who had voted remain had to buckle down and get on with it. He was fed up with people talking Britain down. What remainers had to realise was that they were suffering from false consciousness. All their worries about Britain becoming small-minded, racist – don’t mention Turkey – and broke were just nonsense. The negotiations were all going brilliantly.

The foreign secretary didn’t really have any hard facts to back up his Panglossian vision of a deregulated world with Britain at its centre, free to do whatever it chose, whenever it chose. What he did have was a few lame tropes. Britain wouldn’t be inward-looking. People would still be free to go off to Thailand to indulge in a little casual sex tourism. No one laughed. A bead of sweat broke on Boris’s forehead. It was all going horribly wrong. He then squeezed in a dogging reference. Still no one laughed.

By now he was beginning to look a bit panicky and started bouncing up and down on his heels. Willing his audience to show him the love he craved. He tried a funny word. Brexichosis. Nothing. In desperation he even fell back on the tired Prosecco joke.

Somebody asked him for clarity. “Carrot,” he said, hoping for one laugh from somewhere. None came. “Carrot,” he repeated, digging himself in still deeper. Clarity carrotty. Even the hardline Brexiters in the audience now realised this was the wrong speech by the wrong person at the wrong time.

He did end with one act of unintentional self-awareness. “I’ve always been loving and caring,” he said. He has. But only for himself. When he left the stage, the applause died almost before it had started. Only then did a deeper layer of pathos become apparent. Because however delusional Boris may have been, his speech must have been signed off by the prime minister. Bums together, down on the waterfront.