Once upon a time, the insolence demonstrated by Emmanuel Macron in his fish war with the United Kingdom would have been met with a firmer response than inviting the French ambassador to the Foreign Office for a chat.

Bombarding the ramparts of Saint-Malo hardly seems on the menu today, however – even were our navy capable. Boris Johnson has promised to do ‘whatever is necessary’ to protect British vessels but threatening ‘rigorous checks’ on French boats is as feeble as it is improbable, given that the Royal Navy has just eight small boats patrolling 756,000 square kilometres (300,000 square miles) of water, almost four times the surface area of Great Britain. It’s akin to two police cars patrolling all of England, Scotland and Wales. Britain is demonstrably incapable even of rigorously checking the English Channel.

It’s still two days until the official kick-off on November 2 of Macron’s ‘rétortion’ for the denial of a handful of fishing licenses to French scallop boats. But as early reports trickle in, the latest conflict between the French and the British seems to be playing out well for the president.

Macron has already seized one British fishing boat and threatened others. Ship trackers appeared to show a French warship manoeuvring in the Irish sea. He’s closed French ports to British fishing vessels unloading their catch. And he has threatened next week to impose intensive customs checks on the Channel Tunnel, obstructing thousands of trucks per day.

To dismiss this as some kind of French farce, as initially I did myself, is misjudged. This conflict could cause severe economic disruption and might even lead to people getting killed or seriously injured, as happened in the notorious, now practically forgotten, British cod war with Iceland half a century ago (which Britain lost).

That this has little to do with fish seems incontestable. This is about Macron’s re-election. The disproportionality of Macron’s aggressive response (there have even been threats to cut French electricity connectors to Britain) raises a fundamental question about whether Britain’s attempt to build a relationship with the current French president is even sustainable.

A friend in Paris with connections to the Elysée tells me there’s a faction around Emmanuel Macron that truly, deeply loathes the United Kingdom. Whether Macron shares this visceral distaste might not be that important. He famously married his drama teacher, 24 years his senior, and knows how to play a part. He’s obviously convinced that tantrum diplomacy is likely to be a vote winner.

He may or may not be right that this will be popular. Voters mostly dislike and mistrust him. Many are far less anti-British than advertised. A new poll shows 60 per cent don’t want him to stand for re-election. Fewer than 5,000 are occupied with scallop fishing. But some might be influenced by this manufactured drama and right now, Macron is running scared. Marine Le Pen, his preferred opponent in the second round of next year’s presidential election is fading. He could be facing much more formidable opposition in the shape of the rightist polemicist Éric Zemmour.

The EU, with many other fish to fry, thus far has declined to get officially involved on Macron’s side, but commissioners are privately briefing for France and Macron’s diplomats and politicians are leaning on them. Macron is being solidly supported by the media in France, which gleefully reports every new threat from his ministers. Le Monde said yesterday afternoon that Macron has acted only after a series of provocations including the Aukus submarine deal, agitation over the Northern Ireland protocol and migration. It’s only a matter of time before Macron shows up in Saint-Malo and the first polls, albeit of dubious credibility, appear showing public support for the president’s hard line.

This weekend, Macron will meet Boris Johnson at the G20 in Rome and it will be astonishing if the president doesn’t seize the opportunity to perform another theatrical gesture of some kind. He’ll have further opportunities to act out next week at the climate conference in Glasgow.

What should the British government do? While the UK appears to have an entirely reasonable case, I can find no evidence that any attempt whatsoever has been made to explain it to the French. Menna Rawlings, the new British ambassador to Paris, whose embassy is a Remainer bastion, had, as of early this morning not even published a tweet for two days, other than a picture of the embassy on Friday night, wishing everyone a good evening. There are no Francophone British spokesmen on the French news channels. This isn’t just a fish war but an information war and here, Britain isn’t participating, never mind winning.

French officials cranked up their threats against Britain on Friday afternoon, with prime minister Jean Castex demanding that the European Commission intervene on the side of France. Britain must be punished to show that ‘leaving the EU is more damaging than remaining,’ he said. Meanwhile, the British government appeared to have shut down for the weekend.

Johnson is now going to have to do more than crack bad jokes in franglais. At the beginning of the week Johnson could justifiably keep a lowish profile, waiting for Macron to make an ass of himself. As the week ends, he is going to have to recalibrate. Macron’s deranged, almost Trumpian, diplomacy seems to be trumping British sangfroid. Johnson is supposed to be the great communicator, but seems to have stopped communicating.

It’s a tragedy that Franco-British relations have sunk to this low, over so little. I disagree with the headline on the otherwise informative piece published earlier here by James Forsyth. British-EU relations are not now ‘threatened.’ They have collapsed. Britain and France should be looking for ways to grow richer together and meet challenges together. Instead, we have this.

It’s time to recognise that Macron is a fundamental obstacle to any thought of a constructive, non-contentious relationship. It’s not an exaggeration to say that five more years of Macron, should he be re-elected, presents a clear and present danger to the future of the United Kingdom itself.

A banner currently displayed outside the French embassy in Dublin proclaims France to be Ireland’s closest European neighbour. Northern Ireland is sure to be the next lever he will use to attack the union: stirring up Scotland will follow. Scottish first minister Nicola Sturgeon is said to have cultivated a close relationship with the French in Edinburgh.

The British response to the fish wars must be less pusillanimous. Macron’s re-election would be a disaster for Britain, not just the French. Strengthening him by capitulating would be a disaster. This time, it’s Macron who needs to be humiliated. The time has come for regime change in France.