When Boris Johnson was still in Downing Street, the sound of “bye bye, Boris” being blasted out at full volume to the Bay City Rollers’ tune by campaigners on the streets outside was a regular feature of Westminster life. The song returned for the first time in months on Wednesday as the House of Commons’s privileges committee met to take evidence from the former prime minister. Afterwards, one Conservative MP, hands over their ears, was overheard remarking darkly: “It really is bye bye, Boris this time.” It wasn’t just Johnson’s performance at the committee that suggested his frontline political career could really be over. It was also the scale of the rebellion on Rishi Sunak’s Brexit deal, the defining issue of his predecessor’s premiership. Just 22 Tory MPs voted against, including Johnson, a far cry from the height of parliament’s Brexit wars. Despite an abnormally high number of abstentions, the once mighty European Research Group of hardline Tory MPs who helped propel Johnson to power barely landed a blow. The next day’s newspaper headlines made grim reading for Johnson, but none more so than his journalistic alma mater, the Daily Telegraph, which had been supportive of his premiership right up to its messy end. “The cults of Boris and Brexit are simultaneously imploding,” read the headline of a front page comment piece. The article suggested the “distant sound of a fat lady singing” could be heard in the corridors of power as Johnson was questioned over whether he had lied to parliament over Partygate, and MPs simultaneously voted on the Northern Ireland protocol deal. His plans for a Cincinnatus-style comeback, it concluded, now had the feel of the last days of Rome. After the hearing, centrist Tory MPs shared a sense of relief. “I think he’s done,” one said. “The hearing reminded everybody of the chaos that he could unleash again on the party and the country. He went out on a limb on the Brexit vote but hardly any of my colleagues rallied behind him. We’ve all had enough.” Yet Johnson’s closest allies predict he could once again defy the laws of political gravity. “I don’t think it is the end of the road,” said Stephen Greenhalgh, an old City Hall deputy who was given a peerage by Johnson. “I think we haven’t seen the last of Boris in politics. There’s more to come.” But even his own supporters don’t think it could happen any time soon. The former business secretary Jacob Rees-Mogg said: “The idea that people like me are waiting for an opportunity to shoe-horn Boris in is crazy. To change leader again would be hara-kiri as far as the Conservative party is concerned. “The only circumstance in which we would do it is if we were so far behind in the polls that it was the only option to prevent us losing the next general election, and then why would Boris want to do it? Does that mean he’s a busted flush? Absolutely not. As we see he is still the biggest box office draw in British politics .” However, Rob Ford, a professor of politics at Manchester University, said most Tory MPs appeared to be belatedly catching up with a public who had viewed Johnson as “a busted flush” for more than a year. “The polling has been extraordinarily consistent on this ever since the stories started to break – most people think he’s a liar, most people think he broke the rules, and most people strongly disapprove of it,” he said. “The strange thing has been this spell that he has managed to weave over parts of the Conservative party, with some people thinking he can lead them to an election victory. He’s less popular than Jeremy Corbyn and they didn’t think he was an electoral asset. “But as with all these things, eventually the penny drops, and Wednesday helped do it. You had the concatenation of a diminished Johnson sounding like a tetchy schoolboy, and Sunak sailing through with his Stormont brake despite Johnson gambling on rabble rousing against it.” Henry Hill, the deputy editor of the ConservativeHome website, agreed that Johnson had “passed the peak” of his frontline political career. “It’s difficult to see a pathway back to power for him now. The hardcore of supporters is now quite small. “The pathway that exists is if the Conservative party is still doing badly in a year, with a general election looming, the economy performing poorly and the poll gap not narrowing. But it’s still a fairly slender chance of that happening because changing prime minister again in one parliament could be disastrous.” There are even early signs among the Tory membership, where Johnson’s most committed support lies, that the party is moving on. A ConservativeHome members survey this week found a quarter of respondents believed he should return to No 10 before the next election, but two-thirds said that he shouldn’t. Sunak, whose allies have been buoyant since Wednesday and are claiming that “it’s his party now” after a few weeks in which government appears to have been operating as it should, will try to bolster that when he addresses the Tory grassroots at the National Conservative Convention. There are also whispers that Johnson’s decline, temporary or otherwise, reflects a broader crisis for the right of the party. There is not an automatic crossover between his supporters and the Tory right, but there is much overlap. The problem for the right wing of the party, Ford argued, was that while it had long been a series of factions with converging interests, the issue that had united them – Brexit – was also now declining in significance. Johnson was a “political illusionist” who was able to be whoever he needed to be, characterising himself as a “Brexity Hezza” to unite the party, Hill added. But the appeal to the right was primarily over delivering Brexit. “There’s no reason for the Conservative right to be as loyal to Johnson as they are. It speaks to an ideological inconsistency in the party.” The most unified of the different factions had been the small-state rightwingers, but they remain traumatised by Liz Truss’s disastrous brush with power, and the anti-Brexiters have long been in retreat. Meanwhile, those focused on nationalism and anti-immigration have been largely co-opted by Sunak’s small boats policy. The group incorporates many of the “red wall” MPs who are defensive over fears they could lose their seats at the next election. Many of them recognise that Johnson helped them to win in the 2019 landslide, and also that his star has waned. But they don’t yet – and possibly won’t ever – believe Sunak is the answer. While the splintering of the Tory right keeps the prime minister safe internally for now, it bodes badly for his electoral coalition.