Boris Johnson’s meandering recent speech, in which he lost his place and blathered about Peppa Pig, was consistent with what we have come to expect of the prime minister. So the fact it was monstered by media commentators is bemusing. Johnson has long given up on topics halfway through, asked underwhelmed audiences to applaud him and babbled about painting model buses. Yet his latest shambolic presentation has been treated as a signal that his premiership is disintegrating. It suggests that media outlets have decided to apply a new filter because, as far as Johnson’s public persona is concerned, nothing has changed. Johnson is often described as a Teflon politician, but this non-stick coating must be applied by someone. Three years ago, a Tory MP batted away my suggestion that Johnson would become prime minister. His colleagues, you see, would never allow it. The parliamentary Conservative party regarded him as completely unsuitable to be national leader, because he was selfish, incompetent and morally abject. As such, the MP told me, his colleagues would not permit him to make the final two on the shortlist for members to adjudicate. Months later, this same politician recorded a video endorsing Johnson’s leadership bid, bursting with fulsome praise to the point of sycophancy. Tory MPs had rallied around someone they knew was a charlatan because they believed he had unique properties to defeat the twin menaces of Farageism and Corbynism. Michael Gove notoriously overturned the Johnson leadership bandwagon in 2016, declaring his Brexit brother-in-arms unfit to govern, while Dominic Cummings openly confessed to helping Johnson to become prime minister despite knowing he was unsuitable, purely because he was a convenient blunt instrument to deliver Brexit and smash the Corbyn project. Johnson’s true nature was hardly hidden from media outlets either. An interview with Eddie Mair eight years ago was a striking outlier; the broadcaster savaged Johnson over being sacked twice for lying and conspiring to beat a journalist up – concluding “You’re a nasty piece of work, aren’t you?” By contrast, most of the British media conspired to present Johnson as a rib-tickling performer, allowing him to spin political liabilities into charming virtues. Yet even with this protective shield, Johnson has never been popular, never coming close to the approval ratings enjoyed by all four of his prime ministerial predecessors in their first few months. Johnson’s unique capacity to “cut through” to the British public is a myth. But how the narrative changes: Johnson has gone from the genius defier of political gravity, to a shambolic punchline, and now to a joke. One Tory MP even declared recently that “a bowl of soup could have beaten Jeremy Corbyn”. Yet this retelling of history contrasts starkly with the public image that the press has confected around Johnson up until now. When the Telegraph declared the 2019 election result a “personal triumph for Boris Johnson”, he was widely regarded as a vindicated political titan. That Johnson’s government is defined by corruption should hardly surprise the media. His ex-lover, Jennifer Arcuri, has spent years alleging that as Tory leader he used public office to further her business interests. That Johnson shamelessly breaks solemn promises is entirely consistent with his entire character: as his former colleague Peter Oborne writes: “I have never encountered a senior British politician who lies and fabricates so regularly, so shamelessly and so systematically as Boris Johnson.” Indeed, Johnson’s flaws are anything but subtle. Our media outlets knew all this, but were possessed by the same terror of the alternative as Tory MPs. That included many who fear the left more than the right, privately believing Johnson – who provoked a surge in hate crimes after comparing Muslim women to letterboxes and bank robbers a year before becoming prime minister – was a lesser danger than his opponent. Some persuaded themselves that Johnson was himself a liberal alternative to the Stalinist authoritarianism of Corbyn. He had a “political philosophy … that he will not restrict our liberties unless there is an overwhelming reason to do so,” suggested ITV’s Robert Peston. As prime minister, Johnson has appointed pantomime authoritarian Priti Patel as home secretary and cracked down on the right to protest. Johnson’s team must surely be bewildered by the sudden emergence of media scrutiny. During the early days of the pandemic, when British hospitals were being overwhelmed with dying patients because of the government’s mishandling of Covid-19, this was not presented as an existential crisis for Johnson. Yet the Peppa Pig speech is given as reason to question his political future. The nation’s media outlets have gone off script. When Nadine Dorries, the new culture secretary, reprimanded the BBC’s Laura Kuenssberg and proclaimed the left has hijacked social media (even though Twitter’s own research shows its algorithm benefits rightwing news sources), she underscored the extent to which the Tories can usually count on media compliance. So what explains this sudden shift in the way that Johnson’s premiership is being discussed, both among Tory MPs (some of whom have allegedly issued letters of no confidence) and media outlets? The answer is unremarkable: Johnson has served his purpose. Most Tories do not believe a Keir Starmer premiership is likely and will brutally dispose of Johnson if that calculation changes. Besides, thanks to Starmer’s efforts to recast his party as the establishment’s B-team, a Labour government does not present the same terror as one led by his predecessor. The significant danger for Labour is that a shift in Johnson’s popularity among despairing Tory voters won’t be due to any enthusiasm they hold for the opposition: the decline in Tory support has been driven by its voters shifting to the “don’t know” column rather than to Labour. Starmer’s team needs to present a compelling alternative that motivates the electorate to vote for it, rather than relying on disillusionment with a man who, in any case, may be thrown overboard. For Johnson, meanwhile, this must be a sobering moment. It seemed as though he could get away with anything. And indeed he could – until, suddenly, he couldn’t. Owen Jones is a Guardian columnist