In his account of his first successful general election campaign in 2001, Boris Johnson confesses to a dread of the candidate’s random contact with the public: “Walkabouts generally provoke psychic stress. You can’t just walk up and down, beaming. People will try to ignore you. It is necessary to accost them whether they seem interested or not.” It is surely also a sign of stress that Johnson’s handlers concocted a now infamous video that acts out his fantasy version of a walkabout instead, with an unseen young man asking him really hard questions like: “Hey, Boris. You awright?”; “What’s on your mind today?”; “How do you typically start your day?” and “Marmite, yes or no?”, all filmed on the mean streets of Conservative party election HQ.

As we’ve seen time after time in the campaign, Johnson is no good at faking intimacy, even in highly controlled settings

The video served mainly to remind us that Johnson’s great appeal to the Tory party members who voted for him – that he is brilliant with ordinary people out on the campaign trail – is a dubious proposition. In his limited amount of “random contact with the public”, as in the televised debates in which his bumptiousness is so at odds with the intimacy of the medium, Johnson seems barely to make real contact at all. He is like one of those unfortunates employed in Disneyland to walk around in a Mickey Mouse suit and greet customers with exaggerated gestures. Except that he is dressed not as Mickey but as another cartoon character – Boris.

There is now a fundamental problem with the public persona Johnson has constructed so successfully. The persona is not just “Boris” but also, in a more complex formulation, “Boris being Boris”. “Boris” is the character in a long-running comic saga, written, performed and partly produced by Johnson himself. He is an idiot savant, a hapless bumbler who nonetheless tells it as it is. “Boris being Boris”, on the other hand, is the excuse for racism, for homophobia, for constant lies. It has been, for Johnson, a perfect coupling: whenever Boris is a bad boy, whenever he is peddling falsehoods and nastiness, it is just that “Boris being Boris” sometimes involves going too far.

But these twin personae begin to come apart when the clown becomes the ringmaster. It is one thing to be attracted to the Boris persona, quite another to place your trust in “Boris being Boris”. The election campaign has revealed an underlying tension between what Johnson is and what he does. The first part is an asset; the second an anxiety.

The one thing Johnson has going for him is the power of celebrity. He has been famous for 20 years now. When he ran for parliament in 2001, he was “stunned” to be approached by a uniformed policeman who diffidently asked him for his autograph. Fame is an effective substitute for intimacy. As he put it himself at the time: “It makes people sure they know you, and their reactions to you become personal and rather deluded.” Fame itself does the personal stuff that Johnson cannot do. As we’ve seen time after time in this campaign, he is no good at faking intimacy, even in highly controlled settings and even with easy targets, like the little kids whose schools he invades. He is no good at it because he is really not interested in anyone except himself. Johnson’s staged campaign stops say “Look, here I am!”, never “Here you and I are together.”

Yet perhaps he doesn’t need to be good at it. Perhaps it is a category error on the part of his handlers even to try to make Johnson look as if he is out connecting with people. For with fame it works the other way around – if you’re a celebrity, people already feel “sure they know you”. Johnson is “personal” for voters in the way a long-running character from EastEnders or the Archers might be. The delusion of intimacy is baked in to the whole “Boris” act. Conversely, the more Johnson tries to act like a real person, the more he raises uncomfortable questions. What’s he “really” like? Is he really kind to children and animals? Does he actually give a toss about the rest of us? He would surely be better off surfing his celebrity (as Donald Trump did in his campaign rallies) rather than trying and failing to look like a normal human being.

But that still leaves the problem of “Boris being Boris”. Johnson in his 2001 campaign diary has that rarest of things: a moment of shame. He makes a facetious speech about mad cow disease and upsets beef farmers in his constituency. A whole new planet swims into his ken – the idea of consequences for other people: “I hated myself in that instance for not having the imagination to see that people’s livelihoods were at stake.” The instant obviously passed quickly. There is little evidence he has ever felt this justified self-hatred since. “Boris being Boris” meant never having to feel ashamed again.

Yet the very success of this shtick has stretched its astonishing elasticity of evasion to breaking point. If a man does not have the imagination to see that people’s livelihoods are at stake in everything he says and does, should he be running the country? A smarter opposition might be able to make that a central question of the election. If it can’t do so, the man in the Boris suit will keep waving at the customers in his very own theme park.

• Fintan O’Toole is a columnist with the Irish Times and author of Heroic Failure: Brexit and the Politics of Pain