It can’t be true? The home secretary is seriously preparing for “civil disorder leading to widespread unrest” with a “real possibility” that soldiers will be deployed on the streets to cope with “shortages of food, medicines and other goods” as crime rises. It could last for three months, reports the National Police Coordination Centre, and Sajid Javid tells the BBC’s Andrew Marr he agrees: “We need to prepare for all contingencies and it’s absolutely correct.”

That’s how low the delinquents in the Conservative party have brought us as they dash headlong for a no-deal Brexit. Last week the Whitehall civil contingencies unit held a two-day emergency meeting, not preparing for war or plague but for the calamity we are deliberately inflicting on ourselves, with no upside. No deal “would not be the end of the world”, says the prime minister: that’s a rather low bar.

There is a certain grim merriment to be had from the Brexiteers’ inability to set out any plan for leaving the EU. All these decades of Europhobia and still no publishable Brexit blueprint. With only 200 days left they had to shelve Jacob Rees-Mogg’s 140-page European Reform Group plan at the last minute. What they came up with is such a raving ragbag of rightwingery that they dare not launch it into the light of day. But this is who they are, with their Faragist fantasies bubbling inside Tory politics all these years. The “catastrophic split” predicted by the former minister Steve Baker runs deeper than splitting from the EU.

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The recipe is enormous tax cuts, “to give everyone a Brexit bonus”, both households and businesses. At the same time they promise a mammoth uplift on delusional defence spending – a standing “expeditionary force” to defend the Falklands, and untold billions for Reagan-inspired star wars missile defences as yet uninvented. How is this to be paid for? You can see why they dared not let this stuff out to the Institute for Fiscal Studies.

Boris Johnson picked up the tax cuts plus wild-spending plan in his Daily Telegraph column, urging cuts to income tax, capital gains tax and stamp duty, while promising that £20bn for the NHS and much else too. In his sunlit uplands, “a post-Brexit Britain will be a happy and dynamic economy that fosters enterprise, that rewards strivers and the innovators and where people can hope to take home more of their pay to their families”. He extols Trumponomics as the great recipe for success “to liberate and energise people”, despite the lack of evidence that Trump has done any such thing. All to be paid for with that particular rightwing magic money tree – the Laffer curve – which, Johnson says, proves “that if you cut the right taxes, you can actually increase receipts for government”. This long-discredited theory, so convenient for the rich, has been exploded by the International Monetary Fund – no lefties – which finds that virtually all countries could raise top rates far higher and bring in significant extra sums. The UK could raise top tax to an optimal 60% or more before losing more than it gains.

Check the economic bible, The New Palgrave Dictionary of Economics, summarising all research, and it finds a Laffer effect doesn’t kick in below a 75% top rate. But don’t expect Laffer to disappear from the lexicon of bad reasons why rightwing governments can cut taxes while pretending to preserve public spending.

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How else will they pay for uncosted tax cuts? Some say with that £40bn Brexit bonus when we walk away with no deal, taking our money with us. But if the UK refuses to pay the sum we agree we owe under past contracts, then no deal will mean just that. Renege on our debts and expect no commonsense EU side-deals on essentials, but a crash landing – no aviation, blocked ports, mayhem beyond imagining. Some of these Brexiteers are true revolutionaries who relish the sound of breaking glass.

Johnson and Rees-Mogg seek a deep diminishing of the state, with a low-tax retreat from public to private provision of services. That has been at the heart of true Brexitry from the start, the loathing of Brussels only an extension of deep-rooted anti-statism. When the Brexiteers call for no deal, on World Trade Organization rules, they want a wide-open free trading free-for-all, as their Hayekian high priest of the free market, Prof Patrick Minford, has spelled out to me. Their vision of Britain’s future has no barriers, no regulations, cheap goods, and food from everywhere regardless of chemicals or hormones, regardless of the destruction of our farming and manufacturing. Leave what he calls “metal-bashing” jobs to cheaper countries, though that imposes a dose of the 1980s disruptive “reallocation of labour” from the days he was a Thatcher adviser.

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Thatcher, Reagan and Trump – these are the models for the Boris-Moggites. They will not be affrighted by the next rollout of no-deal technical notices from the special cabinet meeting this Thursday. The Institute for Government tells me the first ones warning of huge finance disruption were the least frightening: they are delaying the most terrifying for as long as possible.

More moderate Brexiteers call for a “Canada” deal – Canada sounds so reassuring. But this deliberately ignores the Irish border crisis, the place Rees-Mogg said he didn’t need to visit, the issue Johnson waves away as the “tail” wagging the Brexit dog, the one whose historic significance escapes the Northern Ireland secretary, Karen Bradley, altogether. That contempt for the Irish runs deep in the Tory right’s DNA. Brexit is a belief, a culture, a tic, an instinct, racist in many of its manifestations. They dared not print a manifesto that exposed them in all their political nakedness. Theresa May should call their bluff.

• Polly Toynbee is a Guardian columnist