I don’t have enough fingers to count the things Nick Boles and I disagree on. The independent MP for Grantham and Stamford only recently resigned the Conservative whip over the party’s refusal to compromise over Brexit. But I can only concur with his clear explanation of the crisis within his former party: “Johnson is truly Britain’s Trump. There is no institution, no relationship and no international commitment that he is not willing to sacrifice to achieve a no-deal Brexit. He is turning the Conservative and Unionist party into the English National Party. He must be stopped.”

The only coherent thing to do in the face of such orchestrated chaos and confusion is to put the national interest first

This is what Conservatives rebels are now facing up to: the party of conservatism and traditionalism, the self-styled party of business and status quo, has been taken over by the British wing of the Trump-and-friends franchise. A grumbling Euroscepticism, nurtured over decades, has festered into a ravaging virus and infected the entire body. It is no doubt difficult to recognise fundamentalist demagoguery when it shows up inside your own party, but recognise it they must. This morning, moderate Conservative MP Justine Greening, widely respected across parliament, looked this reality in the eye and took the honourable decision to stand down at the next election, citing “concerns about the Conservative party becoming the Brexit party”.

Since the EU referendum in 2016 there have been ominous warnings: Theresa May’s horrible “citizens of nowhere” speech, the attacks on judges, the civil service and remain MPs, the shocking disregard for the union, the jaw-dropping “fuck business” attitude, the attempts to keep parliament in the dark about Brexit and then the sight of a Conservative government actually in contempt of parliament.

At various points in this toxic, reckless journey, Tory rebels have shied away from siding with the opposition to try to cauterise the damage. Caroline Spelman came out against her own amendment in March, and Dominic Grieve even voted against his in June. Perhaps these MPs were made assurances by a leader who reneged – and is now gone. But now, with Johnson in charge, we have a prime minister who is willing to shut down parliament, and a senior cabinet minister suggesting the party is above the law. Johnson is even willing to threaten his own MPs with deselection if they vote to prevent a no-deal Brexit. If Jeremy Corbyn was doing this it would be decried by the rightwing press as a vicious Stalinist purge.

Conservative MPs – including some former ministers recently relegated by Johnson to the backbenches – have, commendably, expressed their determination to vote against the leadership. Perhaps his bullying tactics have backfired. But he keeps raising the stakes regardless. In his Downing Street speech on Monday night, visibly flustered by the loud chants of “stop the coup” from nearby protesters, Johnson said rebel Tories would “chop the legs out” from the UK’s Brexit negotiations and threatened them with an election. This may cause some to waver. Added to which, Labour MP Jess Phillips told me: “Almost every Tory MP will tell me how awful it is their colleagues are being threatened with deselection or how they don’t want no deal – they’ll speak freely in the tea room and then go and vote with him [Johnson].”

And there’s an additional problem: some Conservatives might be nervous that Johnson seems to be goading them, trying to engineer a scenario whereby politicians have somehow “forced” him to call an election. The immensely privileged Bullingdon club boy, who wants to give tax breaks to the very wealthiest, then puts himself on the side of the ordinary people against parliament. Hanging over all this is Johnson’s senior adviser, Dominic Cummings. He has been breathlessly depicted in sections of the media as a Svengali-like genius playing multi-dimensional chess, and who has left potential rebels worrying that they are about to fall into his trap.

Yet there has to come a point when the stakes are too high to try to second-guess the gleefully destructive extremists currently at the helm of the Conservative party. The only coherent thing to do in the face of such orchestrated chaos and confusion is to operate on the basis of core principles – chief among which is to put the national interest first.

Johnson, it should by now be clear, is an antidemocratic leader, willing to trash our norms and conventions, his allies and his enemies, in order to hang on to power. Every extortion or demand he makes should now only strengthen the resolve of rebel MPs to put conscience, constituents and country first. Wherever politicians sit in parliament and wherever they stand on Brexit, they must now do whatever it takes to stop him.

• Rachel Shabi is a writer and broadcaster