Life moves pretty fast, as the philosopher Ferris Bueller observed. A week ago, the question was: how come 160,000 Tory members were about to choose the next prime minister? Today, the question is: how come we are suddenly being governed by a rightwing populist single-issue campaign group?

In the past few days it has become quite clear that, at heart, Boris Johnson’s new government is essentially a reunion party for the Vote Leave gang that triumphed in the 2016 EU referendum.

Aside from the prime minister himself, there is his fellow former co-leader of the campaign, Michael Gove, the new chancellor of the Duchy of Lancaster, entrusted with no-deal preparations, who will chair a daily meeting of officials and advisers to orchestrate a speedy departure from the EU.

No 10’s chief of staff in all but name is now the formidably clever Dominic Cummings, former campaign director of Vote Leave. The campaign’s former chief executive, Matthew Elliott, is tipped to join the Treasury as a senior adviser.

Dominic Raab, the spectacularly overpromoted foreign secretary, and Priti Patel, now the helm at the Home Office, were both members of the Vote Leave campaign committee. So too were Andrea Leadsom (business secretary) and Theresa Villiers (environment).

To call this a “coup” is wrong. Much as it may seem otherwise, no rules have been broken (unless you count the breaches of the law committed by Vote Leave in 2016 or Cummings being found in contempt of parliament after failing to appear before a select committee inquiry). But it is certainly a hostile takeover. The wretched balancing act of Theresa May’s premiership is no more. This is politics by purge.

All of which is quite explicit. The more interesting question is: to what end? Cummings made that pretty clear when he addressed the new cohort of special advisers in No 10 on Friday. Though they worked for individual ministers, he said, their first loyalty was to Johnson and his Downing Street apparat. Whatever department they worked in, their primary objective was to achieve Brexit – “by any means necessary”.

No accident, either, that Cummings used a phrase made famous by Malcolm X – a framed picture of whom was prominent in Gove’s office at the education department when he worked there with Cummings. Their favourite conceit was that all those striving to reform the nation’s schools were opposed by what they called “the Blob”: vested interests, public sector unions, unsympathetic civil servants.

Dominic Cummings: master of the dark arts handed keys to No 10 Read more

To beat the Blob, the policy radical had to think and act like the black revolutionaries of the 60s, ready and willing to do absolutely anything in the name of success. You can bet that this bellicose psychological approach has been dusted off and imported to No 10: the new Blob, one imagines, is even bigger, comprising “remoaners”, the media elite, the entire city of Brussels and (quite possibly) 48% of the UK voting population.

I do not think it is strictly accurate to say that the Vote Leave cohort craves a no-deal outcome to this horror show. In 2016, the campaign maintained that a deal with the EU was desirable and achievable.

At the same time, Continuity Vote Leave remains entirely target-oriented. It seeks to win, not to govern. And, in this instance, winning means getting the UK out of the EU by 31 October – “no ifs, no buts”.

Yes, you will hear plenty over the summer about crime, education and the NHS, accompanied by many populist pledges. But all this will be tactical rather than fundamental – a mostly cosmetic propaganda plan to keep the voters on side while the main objective is pursued.

Why the all-consuming urgency over Brexit? One of the Vote Leave gang’s most aggressively held beliefs is that delay is the rust that eats through success. The longer we dither over leaving the EU, the less likely it becomes.

It follows – in their group logic – that further procrastination could wreck all that they fought for in 2016. If leaving by 31 October means doing so without a deal – so be it.

Play Video 1:10 Johnson: 'I do not want no-deal Brexit ... but we must get rid of backstop' – video

Hence Sajid Javid’s announcement in the Sunday Telegraph of “significant extra funding” to prepare the UK for such an outcome, including one of the country’s “biggest ever public information campaigns” – all part of the dismal transformation of Brexit from a supposedly easy act of emancipation to a matter of civil defence. Gove, too, declared in the Sunday Times that “we must operate on the assumption” that we are heading for a no-deal exit.

What does the prime minister really think is going to happen? It is an error of analysis to assume there is a single answer to that question. So great is his faith in the force of his charisma and personal will that he doubtless persuades himself in the long watches of the night that he will make Brussels see sense and agree, with tearful gratitude, to a deal of his choosing.

But you can bet that – five minutes later – he will realise that this is impossible. There may indeed be some scope on the EU side for amendment of the backstop mechanism to manage the Irish border question; but it is the backstop itself, not its form, that a significant hardcore of MPs object to. Likewise, Johnson’s “Gatt 24” wheeze to call a standstill on tariffs for up to 10 years falls at the first hurdle. Using this obscure procedure in international trade law would require all 27 of our fellow EU member states to sign off on the arrangement. Forget that.

During the leadership contest Johnson insisted that the chances of a no-deal Brexit were a “million-to-one against”. We are expected to believe, then, that all this showy preparation for no deal is a Cool Hand Luke bluff by a strategic master? Well, sorry – I don’t buy it. This is exactly what it looks like: a government bracing for a very bumpy exit.

There is no statesmanship in any of this – only campaigning zeal and emotional commitment. As Philip Hammond, Rory Stewart and other MPs do their best to thwart no deal, the Johnson government will simply claim that the defeatists, Europhiles and enemies of destiny are up to their usual tricks: thwarting the will of “the people”.

Remember that Vote Leave was a campaign, not a party. Its business was direct democracy, not the representative variety. No wonder that some senior ministers are so excited to discover that – technically, at least – the UK could still leave the EU on 31 October, even if the country were then in the thick of an election campaign forced by a vote of no confidence.

This is where a country ends up when it is governed by a caucus with a single, overriding objective. Johnson’s strategy, for all its initial brio and swagger, leads nowhere other than a zone of anger, division and dangerous disillusionment. To which his allies would doubtless say: so what? You heard the man – by any means necessary.

• Matthew d’Ancona is a Guardian columnist