Let me caricature a specifically Conservative Brexitism. Of course, there was the Brexit of the much angrier and poorer north and Midlands. This was a Brexit more about distant power, wage suppression, neglect and inequality. But the mild, mainstream Tory Brexiters talked a lot about parliamentary sovereignty, which the Whig tradition had taught them was responsible for British greatness.

Among the Birmingham faithful at the conference, many were still in that camp. If you wanted to be philosophical about it, you could connect it to the conservatism of Michael Oakeshott, as in preferring “the familiar to the unknown… the tried to the untried, fact to mystery, the actual to the possible, the limited to the unbounded, the near to the distant…”

But living alongside that was a very different Brexit. It was a theoretical, ideological Brexitism. It believed that by freeing Britain from EU regulations the United Kingdom could then tear down the social democratic consensus that had been built over the 20th century.

Revolutionary Brexit wanted to return us not to 1953 but to an unfamiliar Americanised world of ceaseless change and raging markets. It was chary about describing this publicly but the position had a certain logic. What was the point of leaving the EU, with all the disruption and friction that involved, without taking a radically different turn?

Much of the thinking in this version of Brexit came from the world of free-enterprise think-tanks so brilliantly anatomised recently by Jeremy Cliffe in the New Statesman (“Liz Truss and the rise of the libertarian right”, September 28, 2022). In terms of pure style, it was exemplified by the smash-the-establishment, non-party radicalism of Dominic Cummings.

Unlike nostalgia-Brexit, this was metropolitan, Atlanticist and deeply critical of the role the British parliament had played in public life. (“Westminster has let the whole country down for many years” – Dominic Cummings.)

“Revolutionary Brexit” is a loose term, and many of its adherents fell away or were expelled in the profound political feuds of post-Brexit London – all revolutionary movements spew out splits and traitors. But it describes something that exists and is now insecurely in power. David Cameron was grandly contemptuous of it. Theresa May struggled vainly to discover a compromise with it. Boris Johnson agreed with it, but only on occasional mornings when his breakfast was disagreeing with him.

If its Silicon Valley, tech-derived motto was “Move fast and break things”, revolutionary Brexit certainly did that. It has kept breaking things until there was nothing left to break. Except, it turns out, the Tory party itself.

This story was confused at a crucial point by the idiosyncratic influence of Johnson. His great political trick was that, uniquely, he could reach across the opposing ideas of Brexit, mixing big-state actions with rhetoric about throwing off chains, using familiar words and homely jokes for Hampshire and reassurance for the Red Wall.

But he was also prepared to impose the illegal prorogation of parliament. Johnson gave a personality answer to a philosophical conundrum – until, of course, his personality (and character flaws) brought him down.

To be fair to Johnson, the pandemic confused the battle lines, giving the state a far more intrusive role than any Brexit revolutionary would have found tolerable in ordinary times. But the fall of Johnson and the rise of Truss marked the final victory of the small-state revolutionaries over the conservative nostalgists.

And – surprise, surprise – they aren’t popular. The country has never voted for this revolution and doesn’t want it. Even Tory MPs didn’t and don’t. This is a revolutionary clique, not real Conservatives, and in Birmingham the party realised it.

So what happens next? As usual, the revolution is devouring its children. Truss can survive but probably only by changing course in a way that leaves her as a poor communicator without a message. Westminster will be more dangerous than Birmingham. She badly needs to buy herself time by postponing impossible confrontations.

I don’t know how or when, but politics is now so fragile that a sudden collapse and an early general election cannot be ruled out, perhaps triggered by some issue we haven’t yet noticed. That would be Tory suicide. One of the ironies of this is that the worse the polling is for the party, the safer Truss may be from a coup (probably botched) that would finish with voters and pencils. Yet as soon as the polling improves, Downing Street will celebrate it as evidence that the policy, whatever the policy is, is working.

Anyway, after the victory of the Brexit revolutionaries over the mainstream Conservatives, who could bring the Tories back together now? Rishi Sunak – the economic arguments he made during the leadership campaign vindicated – would face the hatred of the other half of the party. Boris Johnson won a general election just three years ago, but wounds are too raw for his comeback.

Anyway, personnel is not really the issue. A politics that rejects redistribution and celebrates devil-take-the-hindmost is unpopular and unsustainable in modern Britain. It doesn’t lead to long-term growth. Or social cohesion.

Revolutionary Brexit feels not only like a source of instability but a national dead-end. It has divided us in new ways. It has made us turn our backs on natural allies – the Dutch, Germans and Irish, as well as the French. It has made the international markets look at Britain far more aggressively.

No, this only ends one way. In Liverpool we learned that Labour is getting ready for power, offering that interesting programme – a bit less mayhem. In Birmingham, it seems that the revolution is over, and is now greedily devouring its children.

• The New Statesman report / Andrew Marr