Boris Johnson’s attempt to get a deal with the European Union seems like a speeding car negotiating with a brick wall. The more solid and immovable the wall appears, the harder Mr Johnson charges towards it, claiming he is unable to swerve out of the way. The British prime minister reasons that as both the vehicle and the barrier have a part to play in a car crash, he can blame the collision on the wall because it is made of brick. Hence his laughable claim that Dublin will be as responsible for a damaging no-deal Brexit, should it befall these islands, as Britain is. This is nonsense. It was the Conservative government of Theresa May that negotiated the withdrawal agreement with the European Union. Mr Johnson even voted for Mrs May’s Brexit deal in March because he thought it could be refined in future negotiations. Mr Johnson’s earlier insight – that there are years of negotiations to come in which things can be settled to mutual advantage – seems to have deserted him as prime minister. Mrs May’s failure can be attributed to her flaws, but also to the Conservative party and its hardliners who refused to soften in any way the hard Brexit they favour.

Mr Johnson’s strategy is to weaponise this obduracy simultaneously in international and domestic arenas. This has been a monumental failure. Instead of ending his party’s civil war, Mr Johnson has exacerbated it. His attempt to seize the moment with an early election and mobilise a base of “forgotten voters” has been derailed by a united opposition. Mr Johnson said Britain will be out of the EU by 31 October, “do or die”. Making good on this promise, thanks to parliament, is no longer a legal option.

The central problem with a no-deal Brexit is that it is being cast as providing certainty – a clean break – when it would, as Ireland’s taoiseach, Leo Varadkar, made abundantly clear, do nothing of the sort. Such a scenario would just be the end of the beginning of Brexit. Amid the economic and constitutional chaos of a no-deal departure, the EU and the UK government would have to get back to the three issues the current withdrawal agreement dealt with – the financial settlement, citizens’ rights and solving the Irish border – in a way that will be acceptable to 27 European capitals. Implicit in Mr Varadkar’s words was the understanding that if Mr Johnson thinks he can run an election campaign blaming an intransigent EU for forcing a no-deal Brexit, there would be no amicable sit-down afterwards to hammer out the free trade deal Mr Johnson wants. The Dublin conference is a warning that the rupture could become a permanent rift at the heart of the western world.

No country violates its own interests, but the definition of its interests can change if Brexit’s give and take can be coaxed into the daylight. This is why Mr Johnson’s failure to publish the proposals he has for a supposed deal with the EU, or reports on the consequences of leaving without a deal, has been so deleterious. The exposure of the prime minister’s contradictions in Dublin brings a faint hope that these might reverberate within domestic politics, tipping the balance and mobilising public opinion to shape the attitude of parliamentary factions.

Mr Varadkar indicated that there was, with goodwill on both sides, still much to play for in future negotiations for a free trade agreement with the EU. In a sense the taoiseach was restructuring the Brexit deal to focus on the long-term benefits without backing off from its short-term demands. The message is an important one, emphasising common purpose rather than diverging paths. So is the messenger. Ireland’s leadership has in recent years been viewed as an ally, probably the closest the UK has in Europe, rather than an adversary. Friends can help us face up to the truth: Britain cannot profit from Brexit, but the country will be counting its losses for years to come if it leaves the EU without a deal.