If you don’t like the way Britain is going, move to Scotland.

Nicola Sturgeon’s advice might sound tongue in cheek but she is, she insists, “more than half serious”; after all, Scotland could use the population boost, and plenty of English remainers now find themselves looking for a lifeboat. The hint is that for those not lucky enough to have European-born parents capable of swinging them a second passport, moving north of the border and crossing your fingers for an independent (and pro-European) Scotland in the near future might be the next best option.

Nicola Sturgeon: ‘If we crash out with no deal, Corbyn will be almost as responsible as May or Johnson’ Read more

Cynics will of course note that Scotland’s first minister is no more willing to spell out exactly how another binding referendum could be organised against Westminster’s wishes than Boris Johnson is to explain exactly how the Irish border problem might be resolved, and that both are arguably prone to downplaying the economic risks of dissolving a longstanding union. But Sturgeon is too smart to miss an open goal, and right now Johnson is looking like a gift to her cause given his apparent contempt for Scottish feelings about a hard Brexit. A new poll commissioned by the Tory peer Lord Ashcroft puts 52% of Scots now in favour of independence, the biggest lead since Britain voted for Brexit three years ago, with almost half favouring another referendum by 2021. It’s only one poll, obviously; it could easily be an outlier. But, if nothing else, it’s a timely reminder that the newly belligerent Downing Street line on Brexit may have consequences beyond its control.

This week’s headlines would be the stuff of nightmares for most new prime ministers: sterling plummeting; high streets suffering as consumer confidence collapses; renewed speculation about the potential breakup of the union, not just in Scotland but in Ireland too. But for the new regime in No 10, they’re a sign that the plan is working. We’ve all bought the line that Johnson intends to Brexit in October with or without a deal, no matter what the cost to the economy, constitution or fabric of society. The greater the panic, in some perverse way the better for Downing Street, whose entire Brexit strategy rests on everyone believing that he actually means it.

The jury is still out on whether this is all simply part of some giant, last-minute game of chicken

The jury is still out on whether he genuinely does, or whether this is all simply part of some giant, last-minute game of chicken, both with Brussels and with Tory leavers. Johnson’s case has always been that Theresa May failed to extract concessions from the EU because they never seriously believed her when she said no deal would be better than a bad deal, and his aim now is to convince Brussels that this time Britain really is mad enough to leave at any cost. For the other side to believe such a thing, it does not necessarily have to be true, so it remains perfectly possible that Johnson is just blustering on an epic scale; that all those melodramatic Dominic Cummings briefings to special advisers about how deadly serious the government is were simply made to be leaked. Certainly, the EU’s response for now has been to call Johnson’s bluff and refuse to negotiate on his terms.

But if it is a bluff, the danger is that it takes on a life of its own, setting in motion a chain of catastrophic events that Downing Street might not be able to stop. Real jobs are being shed as anxious consumers, anticipating trouble ahead, start reining in their spending or manufacturers look to retreat from British operations. Those jobs aren’t going to come flooding back overnight even if October brings some unexpected reprieve. Old party loyalties are snapping as MPs ask themselves how far they are willing to go to stop a no-deal Brexit, and that won’t easily be rebuilt. Even if Johnson cuts a deal at the last minute, voters in both Scotland and Northern Ireland are unlikely to forget how close they came to being dragged off a cliff by the English or how they were treated in the process; their concerns ignored, misrepresented and trampled in the rush. Once lit, a nationalist fire is not so easily put out. Brexiteers, of all people, should surely understand that.

• Gaby Hinsliff is a Guardian columnist