There’s a frisson of excitement in the air among Brexiters. The coming crisis brings an eve-of-battle thrill to those who invented all this pointlessness. They relish a cataclysm to blame on the “enemy” across the Channel. “There is hope,” says Jacob Rees-Mogg. “Tick tock goes the clock, and as it ticks down we get closer to leaving. And when we leave, we have taken back control, we are in charge!” Geronimo!

No-deal Brexit will feel about as “in control” as a blindfold skiing novice pushed off-piste from a black run. But it certainly won’t be dull. We have lived 74 years of boring peace on our shores, so the Brexiters savour a faux-war to test our mettle. If you enjoy those olden-days TV shows, Back in Time for School/Dinner, no deal will let us play it at home. Can we still survive hard times? How’s your kitchen cupboard? How’s your nerve? How’s your business and your job? Stiffen the sinews, summon up the blood, it’s time to test our national fibre.

Just to reprise the government’s own warnings: putrid rubbish will fester in the streets, and slurry will stink out the countryside, risking a plague of rats. Sheep will be slaughtered, unexportable with a 60% tariff. Supermarket shelves will empty – it only takes a rumour to set off panic-buying. The NHS may lack medicines. The army and police stand ready for riots, all this costing £4.2bn. You may shrug off Project Fear forecasts – but the pound has already fallen 15%, carmaking has lost 50% investment in a year, and finance is in flight with 2% less growth. The business minister warns that Brexit is a crisis but no deal “will be a catastrophe”. Good grief, even the Queen may flee for fear of us storming her palace.

You see excitement in Brexiter eyes, but their tone has changed. Once they promised lavish trade, a Shangri-La of milk and honey, a deal with the EU “the easiest in human history”. So far, no trade deals have been signed. Today they offer only blood, sweat and tears. They have become survivalists, heroically tightening the nation’s belt.

Their romantics, such as Charles Moore, flippantly yearn for hardship. “I am just old enough to remember when fresh fruit and veg were in short supply at this time of year. People used to know how to store things to mitigate the problem: apples would be carefully laid out on straw-strewn shelves. We ate lots of root vegetables and not much greenery … Perhaps it is time for a Brexit recipe book, like those comforting wartime rationing ones.” Bring back the glory days of smuggling, let us “set out in our little ships to Dunkirk or wherever and bring back luscious black-market lettuces and French beans, oranges and lemons”. Oh, what larks!

The homefront is taught in every school and local museum, often with a misleadingly cosy glow from propaganda posters where happy families eat up their Woolton pie – potatoes, carrots and turnips in pastry – deadly dreary, according to my mother. I wasn’t born in the war, but during postwar austerity I remember going to the sweet shop with ration books.

In phone-ins, older Brexiters say, “People these days have more than enough. It’d do them good.” Imagine digging for Brexit – how many potatoes, cabbages and tomato grow-bags might your garden fit? Look in the wardrobe and think make-do-and-mend, no need for new stuff. It will be good for the planet, good for national moral fibre if shortages bring communities together. I’ve heard people in supermarket checkout queues, only half-joking about stockpiling that extra packet of pasta, waiting for the adventure to begin.

We’ve been here before during 1974’s three-day week, with candles and no TV. The thought arose again when the run on Northern Rock and the 2008 crash revealed secret puritan yearnings. On the BBC’s Question Time a Brexiter man defied the threat to lettuces and tomatoes: “There’s going to be a bit of disruption, but in this country we’re resilient!”

Here’s Dominic Raab sounding battle-ready: “Yes, there are some short-term risks for, say, three to six months. But we can’t allow the EU to bully us.” Man-up everyone, this is war. But here’s the question for Theresa May: just how long would all this pluck and defiance last? What tolerance does this brave island race have for privation? There’s no evidence we are stoical or rational, when petrol queues brought Tony Blair’s government to its knees in days, when leaves on the line and a hint of snow paralyse transport.

I asked David Kynaston, the author of the great social history that started with Austerity Britain: 1945-51, how people might respond to Brexit privations. He found public support for wartime rationing rapidly faded once a good and necessary war ended. Brexit? No chance, with 48% having voted against. Nor will leave voters tolerate what they voted for, he predicts. Even in wartime, crime soared with a thriving antisocial black market – though, in postwar austerity, spivs defying rationing seemed glamorous not villainous.

“Even in a supposedly collectivist decade, people were strongly individualist,” Kynaston says. They welcomed the NHS as “good for me”, but reading mass observation archives, he detected no widespread New Jerusalem sentiment. Ahead, he fears the nationalism that brought us Brexit.

Wartime spirit can be overstated: my mother worked on a fire service switchboard, but she said that in wartime people were no nicer. Ask for anything and the standard jobsworth’s reply was, “There’s a war on, you know.” Don’t expect Brexit to bring out the best in us.

That’s why I remain convinced that May will swerve away from a no-deal kamikaze. The danger is these no-deal scares will make any Brexit deal look benign: it won’t be. On Brexit day, if we enter her transition, nothing will change. Cue sighs of relief that all is OK, but it won’t be. With years more trade wrangling ahead, Brexit Britain will be a slow puncture – we’ll be poorer, meaner, weaker and more nationalistic. No doubt we shall still strut like turkey cocks. No doubt our best export will be nostalgic movies about the war. But the best Brexit is no Brexit.

• Polly Toynbee is a Guardian columnist