At 11pm on the last day of January, it will be precisely three years since the UK departed the European Union, an anniversary that prompts me to ask: how are you enjoying the “new golden age”?

That’s what we were promised by the proselytisers of Brexit, none with more hyperbole than Jacob Rees-Mogg. “The moment of national renewal has come,” he ejaculated on the pages of the Mail on Sunday. “We can embark on this new age with confidence and excitement. Over two millenniums since mighty Augustus quelled the unrest and strife in ancient Rome… our auriferous prime minister is bringing in a new era of revitalisation to our nation.”

The prognostications of Mystic Mogg have proved to be crystal balls. His sleazy Caesar has since been dethroned. Unrest is not quelled. Revitalised is not a word anyone is using to describe a nation stricken with strife. This anniversary will be an occasion for Remainers to lament a tragedy foretold and for Brexiters to – well, what exactly will they do? Recant? Some are beginning to confess that they were wrong. More are looking for someone other than themselves to blame.

They won’t want to be reminded of the sunny uplands shimmering with ripening fruits promised by Mr Rees-Mogg and the rest of the Brexit mob’s false prophets. One of their signature pledges was emblazoned on the side of the chariot that bussed Emperor Johnson – never an Augustus, more of a Caligula – around the realm. You will remember his claim that the subs paid to the EU only had to be redirected to the NHS to transform it into a world-envied health service. Strike one. What we actually have is a collapsing NHS. Another of their boasts was that the UK would “take back control” of its borders. Strike two. Unmanaged migration is not falling, but rising. The most critical promise was that the economy would roar like a liberated lion just as soon as the UK was “unshackled” from the “sclerotic” EU. Strike three. The UK is the sick man of the G7, the only member with an economy that is still smaller than it was before the pandemic. As for that fabled vista of fantastic exporting opportunities for “Global Britain”, businesses are writhing in all the red tape generated by Brexit while the UK has yet to secure a single better trade deal with a significant partner than we had as members of the EU.

Quitting has not been empowering, but enervating. Every credible study concludes that Brexit has introduced new impediments to prosperity while aggravating pre-existing problems. Our trade has had a feebler recovery from the Covid-induced global slump than comparable countries and the inflationary surge fuelled by the war in Ukraine is sharper on these shores than elsewhere. The self-harms inflicted by Brexit also include the suppression of investment and shortages of workers in key sectors. Nothing in the Brexit prospectus has survived contact with reality. Never has there been such a bonfire of vanities.

Some of the advocates for the project now recognise that it has failed and have begun to admit as much. Alex Hickman, a business adviser at Number 10 during the Johnson premiership, recently wrote: “Those of us who backed Leave must acknowledge that Brexit isn’t working… It is not clear to most people what Brexit is actually for.” Some of the champions of Brexit can see it has been a disaster, but can’t publicly admit it – a category that includes members of the cabinet. The Brexit-supporting Tory peer and boss of Next, Simon Wolfson, is among the many who grizzle that this is “not the Brexit I wanted”. Even Brexiters know it looks ridiculous to point the finger at recalcitrant “Remoaners” when Brexiters have been running the government for nearly four years. So now they turn the accusation of sabotage on their own gang by blaming the Tories for messing it up by not doing it “properly”, whatever properly is supposed to be. They sound like those ultra-leftists who claim that Marxism only became discredited as a method of government because none of the various experiments with that creed applied it correctly.

Brexiters in denial can’t admit to themselves that a project founded in delusion, marinated in fantasy, riddled with contradictions and marketed with mendacities was never going to “work”. David Cameron walked off the job rather than try. Theresa May spent three Miserable Years Pursuing a mirage. Boris Johnson lied that he had an “oven-ready deal” and then repudiated the agreement he had himself negotiated. Liz Truss sold herself to her party on the basis that she knew where to find the end of the rainbow containing the pot of mythical Brexit treasure. Her excursion to la-la land was so ruinous that she became the briefest prime minister in our history.

The last and craziest hurrah of the Brextremists is the Retained EU Law bill, conceived by the ineffable Mr Rees-Mogg when he was still in the cabinet and Mr Johnson was still at Number 10. This proposes a mass cull of the EU laws that were turned into British law in the haste to get Brexit “done” and to do so by the end of this year – preserving only those laws that ministers choose to keep or adapt. The promoters of this undemocratic, rushed and reckless scheme are the same people who said that we had all the advantages in the withdrawal negotiations, that we would secure a superb deal and that Brexit would be brilliant for Britain. Now they propose a mission impossible, to review about 4,000 laws, covering everything from environmental protections to consumer rights, in less than a year at a time when the strains on the state are already acute. Business, the trade unions, civil servants and the government’s own assessor agree that it is madness.

David Cameron walked off the job… Theresa May spent three miserable years pursuing a mirage. Boris Johnson lied…

This is but the latest example of how government has spent years wrangling dementedly and fruitlessly over how to make Brexit “work”, time and energy that would have been better spent trying to address our shortage of affordable housing, or improving our chronically poor growth rate, or thinking seriously about how to remedy social care. Mr Sunak and the relevant ministers and officials are presently expending a lot of their capacity attempting to negotiate improvements to the Northern Ireland protocol, which Mr Johnson signed not understanding or not caring how much grief it would cause. I wish success to this quest, but any breakthrough must not be mistaken for a triumph. This is a sticking-plaster operation that will not make things lovely, just a bit less awful. It wouldn’t be necessary at all but for Brexit.

The national mood has become one of Bregret. Pollsters report that those who think Brexit has had a negative impact outnumber those who reckon it positive by more than two to one. Six years on from the referendum, a chunky segment of those who supported Leave are suffering buyer’s remorse. A rising majority of the public now say that it was wrong to leave the EU.

The Brexit headbangers apart, everyone at Westminster knows that we need to mitigate the egregious damage that has been inflicted on this country. The likeliest future is one in which the UK incrementally develops a more sensible agreement with its continent and the rock-hard form of Brexit chosen by the Johnson government is gradually adjusted to a version with less jagged edges. That will be inferior to the terms we enjoyed as a member, but better than the dismal state of affairs now. Jeremy Hunt, the chancellor, would move in that direction, as probably would Rishi Sunak, but they are stymied by fear of the reaction from the crackpots in their party. A closer relationship with the EU would be the ambition of a government led by Sir Keir Starmer. It is the subtext of the Labour leader’s slogan “make Brexit work”.

That’s a disappointment to those who think that what the UK should really be asking itself is whether there is a way to turn back the clock and return to an EU we should never have left. Another product of Bregret is that pollsters now report that a majority of the public say that, given the choice, they would like to rejoin. There’s a vanishingly slight chance of that happening in the foreseeable future because, even supposing that the EU would welcome us back, the politics of negotiating re-entry and then holding another referendum are so incredibly difficult. The sad and cruel truth is that strategic blunders as colossal as Brexit can’t be corrected easily or swiftly. Some mistakes have to be paid for over many years. This, alas, is the UK’s fate. Not a golden age, but ages of regret.