When Liz Truss said ‘the jury’s out’ on whether France was a ‘friend or foe’, Emmanuel Macron publicly corrected her: of course Britain was a friend, he told a TV camera, adding with a grin: ‘Whoever its leaders are, and sometimes despite and beyond its leaders.’ As a British journalist who has lived in Paris for 20 years, I’d call that mostly true. French leaders consider Britain a friend, albeit probably not top five. But Macron and Boris Johnson were often personal foes, and Macron’s relationship with Truss may play out equally badly, especially if French and British differences over Ukraine come to a head in the coming months.

As Johnson noted, the two countries have got on pretty well since Napoleon departed. Remarkably for ambitious military powers separated by just 20 miles of water, they haven’t fought each other since Waterloo, if you discount Britain’s bombing of the French fleet at Mers-el-Kébir off Algeria’s coast on 3 July 1940, intended to keep Vichy France’s ships out of Nazi hands. The attack killed 1,297 servicemen, and is still remembered by some here as the French Pearl Harbor.

The big modern jolt to the relationship was Brexit – a shock to the French precisely because they saw it could have happened to them. When I mentioned to one official that his compatriots in 2016 might have voted for Frexit, he replied: ‘Yes. But we wouldn’t have been dumb enough to hold a referendum.’

Most French people spent about five minutes on Brexit. They had bigger worries, and their far right had its own pre-appointed national enemy in Islam. But mainstream French politicians needed Brexit to fail – not because they are anti–British, but because they are pro-French. Their bogeywoman is the far-right leader Marine Le Pen, who went into the 2017 election against Macron promising a referendum on Frexit. If Brexit prospered, she might too. And so France was even more rigid than most EU member-states in the Brexit negotiations. Macron said that if Britain left the EU’s structures, it would lose all the benefits: ‘There should be no cherry-picking in the single market.’

All too easily, he got his way. The Brexiters are still searching for the sunny uplands, while Le Pen has been crushed by Macron in two straight elections and has shut up about Frexit. It’s hard now to identify a strong exit movement in any EU member-state. You might even argue that Brexit saved the EU.

Brexit aside, Macron has Anglophile instincts. He’s a spiritual Londoner who had just agreed to become a visiting fellow at the London School of Economics when in 2014 President François Hollande appointed him economy minister. Hollande and his predecessor Nicolas Sarkozy spoke risible English, while Valéry Giscard d’Estaing was fairly fluent but thought a French president should only speak French in public. By contrast, Macron, from a new French elite generation, parades his very decent English around the globe, as do his ministers like Catherine Colonna (former ambassador to London), Laurence Boone and Clément Beaune.

Johnson had the trappings of an English Francophile, given his slightly-above-tourist–level, Belgian-inflected French, and his origins: his paternal grandmother was born in France to a French mother, and his father Stanley recently became French (me too!). But Johnson always found France the perfect pretend enemy. Quarrelling with the Germans is hard, given their no-enemies policy. Clashing with Russia or China is high-stakes. But jousting with France is safe, because everyone understands it isn’t really a foe. Also, to Englishmen of Johnson’s stamp, French dignity is irresistibly funny. So the two former superpowers relived their fondly remembered naval battles by fighting a ludicrous ‘fish war’ over licences for about 200 French boats to fish in British waters.

Later, Johnson posted on Twitter his taunting letter to Macron about migrant boats in the Channel. ‘I am surprised by methods when they are not serious,’ replied Macron. (As a guidebook by the French Chamber of Commerce in the UK warned in 2013: French businesspeople ‘will potentially view humour as lack of seriousness’.) The Canard Enchaîné magazine, France’s version of Private Eye, quoted Macron as saying he regretted ‘seeing a great country… led by un clown’. Downing Street and the Élysée relentlessly briefed against each other.

Then Russia invaded Ukraine. Britain had long been close to Ukraine, Tory leaders tend to welcome any war, and Johnson got stuck in. There wasn’t much else he wanted to do in office anyway. Macron came at the issue differently. France is traditionally friendly with Russia. When a French foreign minister once took advantage of a rare shared limo ride to ask Jacques Chirac why, Chirac replied: ‘If I look at the map of Europe, I see lots of nice little countries. And I see one whopping great bear. So I’m friendly to him.’

Macron has endless things he wants to do in office, including remaking Europe and the world. He felt sorry for Ukraine, but like many western European leaders, he didn’t see the invasion as his problem. Modern Russian armies don’t venture as far west as Paris. So what Macron has wanted since the war began – though he won’t say it out loud – is to end it ASAP by brokering some messy ceasefire that de facto hands Putin some conquered Ukrainian territory. That would solve the cost-of-living crisis, and save Macron from spending his ten-year window in power fighting another neighbourhood’s bully. London worries he will lean on Volodymyr Zelensky to settle too early. After Macron said Putin shouldn’t be humiliated, No. 10 inevitably briefed he was Chamberlain.

The French don’t mind the British pursuing their own interests (no democracy pursues its interests more aggressively than France) but they do resent Britain no longer playing by international rules. Like many European leaders, Macron had stopped trusting Johnson even before he unilaterally tried to rewrite the Northern Ireland Protocol, breaking the divorce treaty he had signed with the EU. Now Truss is prolonging the effort.

Still, Macron will donner her un break. Europe’s two serious military powers need each other, especially if a second Trump administration ditches Europe. And anyway, Macron has learned during his years in office that no modern British PM sticks around long.