British politics now follows the tortured pattern of addiction. Inside the addict’s head the most important thing is getting to the next Brexit fix, scoring the best deal. But from the outside, to our European friends and family, it is obvious that the problem is the compulsive pursuit of a product that does us only harm. On Tuesday night Theresa May thought she had scored: a slender majority in parliament voted for an imaginary agreement in Brussels, stripped of the hated “backstop”. Tory Eurosceptic ultras and the DUP pledged conditional allegiance to the prime minister if she delivers “alternative arrangements” for a seamless border on Northern Ireland. But no one has any idea what those might be and the EU has already ruled out a renegotiation on terms that might satisfy the hardliners. The transient buzz of Tory unity will yield to the chilly comedown of Brexit reality, as it always does.

Brexit: Theresa May given two weeks to renegotiate Irish backstop – Politics live Read more

Some MPs can see the situation spiralling out of control. Today 298 lined up to demand an intervention. They backed a cross-party bid to seize control of the Brexit agenda from the government and delay the day of departure if necessary. But the move failed. There is ample horror of the no-deal scenario across the Commons (a vaguer condemnation of that option won a narrow majority), but clearly the greater fear is association with anything that looks like an active plot to thwart Brexit. Yvette Cooper and Nick Boles, sponsors of the more controversial amendment, insisted their aim was only to guarantee an orderly departure, and there is no reason to doubt them. Parliament is packed with pro-Europeans who say no to the hard junk peddled by the likes of Jacob Rees-Mogg but are still hooked on softer strains of the leave drug.

There is a booming trade in legal Brexit highs for MPs. The newest variant to hit the Westminster street is a confection put together by Kit Malthouse, a leave-voting Tory. His product has been endorsed by a remarkable spread of Conservative MPs, from former remainers to hardline Brexiteers. They grandiosely call it the “Malthouse compromise” – as if it were a magisterial vision for peace among nations and not a ragged stitch-up to postpone Tory civil war.

The idea has two parts: first, renegotiate the backstop that promises a frictionless Northern Irish border; second, if renegotiation fails, scrap the deal but salvage the transition period contained within in it. Then aim for an exit on WTO terms.

It is a strange kind of compromise plan that offers no compromise. The backstop only exists because May’s Brexit red lines could not be bent around the Good Friday agreement any other way. As for the transition period, it is a condition of the current deal. The idea that it can be cut and pasted into some other deal presumes that the past two years have just been a warm-up before the real match starts. This new Malthouse doctrine is really the old hardline Brexit delusions in shinier shoes. It is the bluff that Britain holds all the cards, and that if we show enough contempt for treaties and economic logic, Brussels will be intimidated into granting favours that could not be won by conventional diplomacy.

There are two possible reasons for pursuing that strategy. One is stupidity: failure to grasp what the negotiations so far have actually been about and how May’s deal was their logical outcome. The second is cynical vandalism: knowing that the plan will fail and hoping, when it does, to pin blame for a chaotic no-deal Brexit on Brussels intransigence. In truth it would be the fruition of Eurosceptic zealotry.

It is sad to see self-styled Tory “moderates” taken in by such a con and alarming to hear May indulge it in the Commons as a “serious proposal”. Her next move is to Brussels, in a quest for something that two years of negotiation have already failed to uncover. But it seems the way to unite Tories these days is to expunge the period 2017 to 2018 from memory. May still acts as if Brexit is something that must be settled to the satisfaction of the Conservative party first, and only then shared with the rest of Europe. The British public is at the very back of the queue.

Such obtuseness infuriates continental leaders more than the intent to quit their club. It was not a secret that Britain had a Eurosceptic political culture, even if the referendum result was shocking and upsetting. But what was also obvious in Brussels, Berlin and Paris was the gap between the idea of Brexit advertised by the leave campaign – the narcotic rush of words such as “freedom” and “sovereignty” – and the practical business of extricating Britain from EU structures. Angela Merkel, Emmanuel Macron and others presumed this yawning chasm would be recognised by their British counterpart as a hazard. They expected May to start building bridges from the leavers’ fantasy island to the reality of what was available in negotiations with a bloc of 27 countries – the imbalance of power and the calculus of damage limitation.

Play Video 1:49 May says she will renegotiate with EU for changes to withdrawal agreement – video

But May never confronted that logic. When she took the referendum result as her personal mission she also anointed herself with sacred oils of Brexiteer mythology. Her inscrutable demeanour and robotic speeches conceal a fervour that would be instantly identifiable as demagogy in a more expressive politician. At first, the prime minister’s rigid mask tricked Europeans into thinking she was a reasonable and capable person. It had a similar effect on the domestic audience. May’s bland style flattered a collective belief in the innate moderation of our politics. Her parochial mediocrity has nurtured the complacent assumption that the worst cannot happen here, that we are, at heart, a pragmatic nation not given to fanatical lurches. MPs imagine parliament as a political equivalent to the Greenwich meridian – the zero line from which other countries’ deviations are measured. We are slow to notice when the whole enterprise drifts wildly off course.

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Yet no one watching from the outside retains that romantic view of Britain as a bastion of political sobriety. They see instead a weird, stubborn refusal to talk about the crisis in plain English. MPs do battle over amendments to motions that change standing orders to permit bills to insist on extensions to a negotiating period, without saying what they think the outcome of that negotiation should be. Meanwhile, the prime minister invites her backbenchers to vote against something she has agreed in Brussels so she can go back and ask for something that she knows will be rejected.

It is obvious that Brexit is a disaster, yet still so many MPs observe a taboo against saying that it should be stopped. To our continental friends and neighbours it is scarcely comprehensible. It looks like British social awkwardness elevated to the scale of a constitutional meltdown. It is the stiff upper lip chewing itself to pieces rather than name the cause of our suffering: not the deal, not the backstop, not the timetable, not Brussels, but Brexit. The poison in our system is Brexit. We need a path to recovery, not May’s frantic hunt for a stronger, purer dose.

• Rafael Behr is a Guardian columnist