Daniel Hannan is an MEP for South-East England, and a journalist, author and broadcaster. His most recent book is What Next: How to Get the Best from Brexit.

The problem is the backstop. Not the precise terms of the backstop, but the fact of having one at all. Think about it for a moment. We are proposing to enter talks with the EU about our long-term future on the basis of having first agreed that, if those talks fail, we will still make a series of excruciating concessions in order to ensure an outcome that the EU regards as acceptable.

How can any negotiation proceed on that basis? How can we include a backstop that the UK regards as contingent and unlikely, but that the EU sees as an acceptable – indeed, an alluring – permanent settlement? Surely anyone can grasp that, once such a provision were in place, the EU would lose all interest in negotiating any deal – except, perhaps, a deliberately punitive one pour encourager les autres.

I say “surely anyone”, but it seems that British negotiators can’t or won’t see it. If nothing else, the past two years have demonstrated the monumental ineptness of some of our senior civil servants. Back in the 1990s, when the European argument took off properly in Britain, I found Sir Humphrey technically brilliant, if wrong. The scheme he favoured – deeper integration into European structures, including the Euro – was inimical to the national interest, but there was no doubting the skill and tenacity with which he pursued it. Now, though, he seems to be blundering even on the logistical level.

Consider, for example, the assurances that our mandarins kept giving our political leaders that Brussels would accept what Britain was proposing at Salzburg. Almost every casual observer could see that EU leaders were going to say no, as they had to every previous British initiative. But Sir Humphrey, perhaps blinded by his closeness to his European counterparts, or perhaps so invested in his scheme that he could not view it objectively, was blindsided by the rejection.

If it had been a one-off mistake, fair enough. Even our supposedly Rolls Royce diplomatic service might be allowed the occasional engine cough. But the pattern has been repeated so often that it has to be considered a design flaw rather than a glitch. Again and again, British ministers have been encouraged to make some big new concession in the hope of unlocking a trade deal from the other 27. First it was the acceptance of the EU’s sequencing, then of the money, then a unilateral security guarantee, then Chequers itself, now the customs union. Every time, Eurocrats have calmly pocketed the concession and demanded more.

Is it any wonder, given their experience over the past two years, that Brussels functionaries are sitting back and waiting for yet vaster British offers? Can we blame them for holding out for another surrender on the backstop, given their experience to date?

There were reports over the weekend that our negotiators – that is, our civil service team – had already agreed to customs union membership, and that the trouble arose when Cabinet members were presented with the idea. I have no way of knowing whether that’s true, but it would certainly fit the pattern. The history of the European project is the story of officials presenting their notional bosses with one fait accompli after another. The Treaty of Paris, which launched the entire process of integration in 1951, was an almost perfect symbol for what was to follow. Because the final draft was not ready in time for the signing ceremony at the Quai d’Orsay, the six foreign ministers put their names to a blank sheet of paper and left it to their permanent officials to fill in the text later.

Brexit was, at heart, a democratic revolt, a rejection of the dominance of an unelected and unaccountable caste. The question is whether Britain’s democratic leaders will now assert themselves. It was the sense of a civil service stitch-up that, at least in part, prompted the resignations of David Davis, Steve Baker and Boris Johnson, all of whom felt that the work they had been preparing had been undermined by our officials.

The following weekend, the Prime Minister wrote in the Mail on Sunday that Chequers was a take-it-or-leave it offer: “Let me be clear. Our Brexit deal is not some long wish-list from which negotiators get to pick and choose. It is a complete plan with a set of outcomes that are non-negotiable”.

So, when the EU rejected it – and rejected it in a calculatedly mocking and sarcastic tone – I assumed that Britain would withdraw the offer and try something else, either a Canada deal or EFTA or a minimalist accord that would give up on trade and focus on the most basic agreements that all neighbouring states have on such issues as transport, fishing rights and police co-operation.

How extraordinary, then, that we should have rushed forward with yet another offer, this time the most self-harming of all, namely Customs Union membership. A depressing number of Leavers say things like “It wouldn’t respect the referendum result” or “It would be Brexit in name only”. In fact, it would be far worse, because it would oblige Britain to match all EU trade concessions to third countries, while those third countries had to reciprocate only vis-à-vis the EU 27, not Britain. Our home market, in other words – the fifth largest economy in the world – would become a bargaining chip for EU trade negotiators to use wholly for the benefit of the 27 remaining states.

How can anyone, Remain or Leave, countenance such a deal? It must surely be clear that it would represent, from the EU’s point of view, the ideal outcome, better even than a humiliated Britain begging for readmission without its rebate. Why on earth would Brussels want to replace it with a different arrangement? It wouldn’t matter whether the backstop came with a break clause or a time limit. The EU would simply never agree to put a permanent deal in the place of one so favourable, so we’d be back where we are today.

Better, surely, to take the initiative now. The proposed exit terms represent a deal worse than either staying or leaving. We need to drop our sunk costs stubbornness and try something different. I argued on this site, before during and after the referendum, for a Swiss-type deal based on EFTA. But, frankly, any outcome – no deal, Norway, Canada, even the risk of a second referendum – would be better than what is currently on the table. This is our last chance to pull out of the nosedive.