EVEN TRAGEDY, it seems, cannot bring Britain and France together. For a brief moment on November 24th, after 27 refugees died in the icy English Channel trying to cross in an inflatable boat from the northern French coast to Britain, it looked as if tensions between the British prime minister, Boris Johnson, and the French president, Emmanuel Macron, might ease. But this was not to be. For behind the row about migrants lies a fundamental problem: the two neighbours are separated by a narrow channel of water and a gulf of mutual distrust.

Neither side is blameless in this latest spat. The day after the drownings, and without warning the French, Mr Johnson tweeted a letter he had sent to Mr Macron. In it he proposed ideas about better cross-border cooperation, such as the dispatch of British soldiers and policemen to patrol French beaches, which had already been rejected by France as an infringement of sovereignty. The letter also proposed a “returns agreement” to take back migrants who arrive in Britain, which the French have repeatedly made clear is a matter for EU, not bilateral, discussion.

Mr Macron, who was in Rome signing a Franco-Italian friendship treaty, retorted angrily that the letter was “not serious” and that he did not conduct diplomacy by Twitter. Yet days earlier the French diplomatic service had tweeted a clip of Jean-Yves Le Drian, the foreign minister, calling Mr Johnson a “populist who uses all elements at his disposal to blame others for problems he faces internally”. Serious was hardly the word that best characterised the decision by Gérald Darmanin, the French interior minister, to cancel an invitation to Priti Patel, the British home secretary, to a meeting on the migrant crisis. This is due to take place on November 28th in the port of Calais, with his Dutch, Belgian and German counterparts, as well as the European Commission.

Behind this trading of cross-Channel insults, the view in Paris of the underlying problem is twofold. The first is that the French have concluded that Mr Johnson’s government cannot be fully trusted. Although Mr Macron has never liked Brexit, as it weakens the EU, this is not now his real gripe. Two years after the British voted to leave the EU, he went enthusiastically to a Franco-British summit at Sandhurst in 2018, in the hope of building a stronger defence and security relationship with Britain. Yet the French have been dismayed by British efforts not to implement parts of the deal to leave the EU that they had signed. Ahead of the G7 meeting in Cornwall this summer, Mr Macron declared that “this means nothing can be respected.” As if to make his point, details of the two leaders’ private conversation at the G7, concerning sausages and borders, were then leaked, making Mr Macron look foolish.

In September the French were further bruised by AUKUS, a strategic pact between Britain, America and Australia, which was negotiated behind their backs and tore up their own deal to sell submarines and make Australia the centrepiece of France’s Indo-Pacific strategy. Since then, say the French, the Americans have gone out of their way to repair the lost trust; but not the British. The only language that Britain understands right now, conclude the French, is one that involves a show of strength.

The second problem is that the old British reflex of blaming the French, especially when it helps to distract attention from domestic troubles, is becoming politically problematic. Mr Macron faces a presidential election next April, and needs both to be seen to be defending French interests and not letting an affront go unchallenged. Several aspirant presidential candidates to his right, including Michel Barnier, the EU’s former Brexit negotiator, vow simply to let migrants go on to Britain if they wish. By over-reacting, Mr Macron’s government undermines its own claim to be ready for serious dialogue. But, as one French official says, “as long as the first instinct of the British is to blame us, it’s difficult to have a meaningful conversation.”

In particular the French resent the charge that they are not doing their bit to patrol the coastline or to welcome refugees. In recent years, with the help of British finance, they have built up high fencing and tighter checks on freight leaving France through the Channel tunnel, in order to keep migrants from crossing to Britain via that route. This has encouraged people to try their chances in small boats from the beaches instead. So far this year, the French coastguards say that they have rescued 7,800 migrants from the Channel. French authorities have also arrested 1,552 people-smugglers, and dismantled 44 trafficking networks.

Moreover, last year France received 93,475 applications for asylum, the highest number in the EU after Germany, compared with 36,041 in Britain, according to the United Nations High Commissioner for Refugees. Many refugees have family in Britain, however, and do not want to stay in France; some spend only hours on French soil. The French want closer co-operation with EU neighbours, such as Belgium and Germany, in order to try to break up the people-smuggling rings that bring refugees to the French coast in the first place.

“The problem today is that both France and the UK see what the other is doing through their own prism,” wrote Michel Duclos and Georgina Wright in a note for the Institut Montaigne, a think-tank: “ Neither thinks the other side is serious about strengthening co-operation.” In the long run, the two neighbours and allies will need to rebuild confidence and work more closely together. In the short run, the prospect of restoring cross-Channel trust looks lamentably slim.