Just because Boris Johnson approaches every issue thinking only of Boris Johnson does not mean we have to do the same. Even the crisis that now engulfs the prime minister, and sees his fate hang on Tory MPs’ reaction to a Sue Gray report that could come next week, is not only about him. It’s tempting to see it that way – to look for the roots of the partygate scandal in Johnson’s arrogance, entitlement and narcissism – but it’s a double mistake. As a matter of politics, it’s unwise because it would allow the Conservatives to ditch Johnson, pick a successor and claim to be a new government exorcised of its demon, with no need for the electorate to turn to Labour. But it’s also wrong. For Johnson may be a loner, but he did not act alone. That’s narrowly true, in the sense that there were plenty of others who knew about or attended those rule-breaking parties and plenty more who are covering for him now. Every Conservative MP who defends Johnson, every activist or donor who does not demand his resignation, makes themselves complicit in the damage his actions have caused. But it’s true in a deeper sense, too, in that the shaming events in Downing Street are a function of a Conservative party that is now something else. Despite the name, that organisation is no longer conservative in the way that was previously understood and in which it once took great pride. Consider the two parties that Johnson himself did not attend, the ones that rocked the basement and saw a suitcase full of booze wheeled into No 10 the night before the Queen buried her husband. Forget Covid and the restrictions that were broken. There was a time, not so long ago, when no Conservative would have dreamed of partying in a government building on the eve of a royal funeral, even if there was no pandemic. They would have been affronted by the very idea of it. Or take the actions of two of Johnson’s most loyal cabinet ministers as they moved to save their boss. The culture secretary, Nadine Dorries, announced the end of the licence fee, essentially passing a death sentence on the BBC as we know it. Admittedly, Tory ministers have always enjoyed bashing the BBC, threatening to take it down a peg, but they have not called for its effective destruction. Yet now a minister who calls herself a Conservative can look at a world-class, century-old institution that all but defines Britishness, and think her mission is not to preserve and protect that institution but to smash it into pieces. Meanwhile, Jacob Rees-Mogg, who likes to cosplay as an Edwardian high Tory, sought to defend Johnson by attacking the elected leader of the Scottish Conservative party as “a lightweight”, thereby belittling the Scottish Tories who had chosen him. Once upon a time, a member of the Conservative and Unionist party would have understood that the fate of the union is imperilled if Scottish voters believe Westminster regards them with contempt. But Rees-Mogg couldn’t care less. The origin of all this – a Conservative party happily trampling on the union, the monarchy and the cultural organisation that binds these islands together like no other – is not hard to fathom, though it has become impolite to mention it. It’s Brexit that transformed the Conservative party. Where once Tories revered tradition, Brexit filled them with revolutionary zeal. Suddenly, and in a reversal of the teaching of the conservative theorist Michael Oakeshott, they preferred the unknown to the familiar, the untried to the tried, the possible to the actual, utopian bliss to present laughter. Brexit saw the Tories succumb to the lure of abstract nouns – Freedom! Sovereignty! – and supposedly creative destruction. One minister can’t shake the image of Dominic Cummings, minutes after the referendum result came through, leaping on a table at Vote Leave headquarters, giving a speech and then punching a hole in the ceiling: “Destructive fervour in his moment of triumph.” Vandalism became a Brexit habit – hardly surprising for a project dedicated to uprooting a tangle of connections with our continental neighbours that had grown dense and thick over half a century – and this is the Brexit government. Like all revolutionary endeavours, it believes that the end justifies all means, no matter the damage to those things conservatives once cherished. This, remember, was the movement that promised to restore parliamentary sovereignty – only to suspend parliament illegally to get its way. So we should not be too surprised that the Vote Leave Downing Street behaved the way it did. Of course it had contempt for the rules, even those it wrote itself. This was the government that boasted on the floor of the House of Commons of its willingness to break international law, if that’s what its purist Brexit required. And naturally it bridled at restrictions of any kind, even those essential to keeping our fellow citizens alive. A crude libertarianism always ran through Brexit, with Brussels seen as the source of pettifogging rules imposing a nannying health-and-safety culture on John Bull. No wonder Johnson, Cummings and the others thought they were above such things. Freedom was always their rallying cry, and they were going to damn well have it, even as they were denying it to everyone else. Besides, they saw themselves as granted a special licence that put them beyond the reach of the usual constraints. The Brexiters believed the referendum result had given them a super-mandate that trumped any conventions or norms: it made them anointed instruments of the will of the people, who could brook no challenge. The landslide victory of 2019 reinforced that conviction. It was a toxic combination: part Marie Antoinette drinking and laughing while outside the walled garden the obedient public were dying lonely deaths, part revolutionary politburo convinced that whatever satisfied its personal interests served the cause of the people. We need have no illusions about the Conservative party of old. We know its record. We know that Margaret Thatcher had her own kind of revolutionary zeal, just as we know the destructive impact of David Cameron’s austerity. But there were lines it dared not cross, monarchy and the union among them. This is a different animal. Brexit transformed it from a conservative party into a national-populist party. Its instincts now are those of Viktor Orbán, funnelling public money and jobs to ideological allies, ready to burn down even the most valued institutions that stand in its way. Of course, it has contempt for the people, as all populists ultimately do. It even had contempt for the Queen on the night of her greatest grief. So let’s not pretend these faults were Johnson’s alone. Brexit is the virus. Boris Johnson was only ever its most visible carrier. Jonathan Freedland is a Guardian columnist