If EU membership were as onerous as the Brexiteers suggest, the UK would have left decades ago. Instead it has remained a member for nearly 47 years (albeit in a comatose state for the last three).

In the decade before the 2016 referendum, fewer than 10 per cent of UK voters cited Europe as the most important issue. Indeed, as late as December 2015, a mere one per cent did. Only after the Leave vote did its salience spike (47 per cent now name it as the most important issue). In other words, contrary to David Cameron’s claims, it was the politicians who led the public rather than the public who led the politicians.

In a little-noticed piece, Dominic Cummings, Boris Johnson’s senior adviser and Vote Leave’s campaign director, argued last year that an EU referendum was a choice, not a necessity. “The idea that there was an irresistible force for a referendum is pushed by Farage’s and Cameron’s supporters,” Cummings wrote. “They are both wrong. The country supported one but without any passion outside the small fraction who had long been passionate about it. Most Tory MPs did not want it.”

Cameron, who wanted to be prime minister because he thought he’d be good at it, held a referendum because he thought he could win it and “settle” the European question. He achieved the reverse. From the moment the UK voted to leave, the status quo ceased to exist. The spectre of the 2016 referendum will forever haunt any decision to remain in the EU and there is no easy way to leave. What some truly crave is a past that no longer exists.

Since 2016, the UK’s EU membership – like Schrödinger's cat – has been both dead and alive. Will the box soon be opened to reveal its true state?

Boris Johnson, it appears, is now prepared to accept a customs border between Northern Ireland and the rest of the UK – the very solution Britain rejected as unacceptable when it was proposed by the EU in February 2018. The mooted deal is already being forensically compared with Theresa May’s.

But this avoids a more revealing comparison: the deal the UK already has. At present, Britain enjoys full membership of the single market and the customs union as well as opt-outs from the euro, the borderless Schengen Zone and home affairs policy, and a £4.9bn budget rebate. It received – and then rightly reversed – an exemption from the Social Chapter, which guaranteed workers a minimum of 28 days’ paid holiday per year, maternity and paternity leave and equal rights for part-time employees.

The irony of the Brexiteers demanding “flexibility” from Brussels during the Brexit negotiations is that the EU so often showed it before. No member state has ever been granted a better deal – and no state ever will be. Any British prime minister who negotiated such an agreement today would be lauded as a supreme dealmaker (John Major, a man reviled by Brexiteers, may reasonably feel neglected).

True, the EU did not grant the UK greater control of free movement (though its economic and social benefits are plain). But Cameron was awarded notable concessions during his renegotiation of the UK’s membership. They included an official exemption from “ever closer union”, a four-year ban on in-work benefits for EU migrants (activable for seven years) and greater safeguards for the City of London.

In the case of free movement, the UK already has the flexibility to impose greater control. Though EU citizens are initially permitted to live in any member state, after three months they must prove that they are working (employed or self-employed), a registered student or have “sufficient resources” (savings or a pension) to support themselves and not be “a burden on the benefits system”. Far from being unconditional, then, the right to free movement is highly qualified.

Johnson’s proposed deal, should it be concluded, will be lauded as superior to May’s agreement and no-deal. But this neglects the most unflattering comparison: it will be profoundly worse than the deal the UK already has.