If there’s one person who can end the Brexit ‘sausage war’, it’s Joe Biden

So, Brexit didn’t “get done” after all. Indeed, if the remarks of David (Lord) Frost, in effect still British chief negotiator on Brexit, and his EU counterpart Maros Sefcovic are anything to go by, then Brexit may soon be undone, and destined to hang around for years if not decades, poisoning domestic politics and international relationships alike.

This week, on the “margins” of the G7 summit in the uplifting surroundings of the Cornwall coast, Ursula von der Leyen, Emmanuel Macron, Angela Merkel and even Joe Biden will attempt to bypass “Frosty the No-Man” and approach Boris Johnson directly with the aim of winning a compromise. They seem not to realise that, on Brexit, Mr Johnson has mutated from his days as Europhiliac mayor of London to become the most truculent man in the room. They are likely to find the prime minister happy to be at the centre of the world stage, but as pugnacious as ever on the Northern Ireland protocol, fishing, and much else.

Things are looking down for the British-European “partnership”. The war of words has turned into a row, nicknamed the “sausage war” – a deliberate trivialisation by the UK of the issue of food safety – and there is every sign that more court actions and selective trade sanctions will follow. The result will be an uneasy coexistence, an economic cold war between the UK and EU, with the terms of Brexit never quite settled. The Europeans probably do tend, as Lord Frost says, towards “legal purism” and legalistic solutions and precise rules; the British tend to be overly careless of their international treaty obligations, preferring “political” answers. These cultural differences have snagged the talks for five years, and continue to do so.

The prospect of the EU slapping quotas on British car exports, or punitive tariffs on fish, or barring City firms from EU financial business, is too horrible to contemplate. Mr Johnson can threaten to retaliate with parallel penalties on German cars and so on, but a tit-for-tat trade war will leave everyone a loser. Both sides could do with a cooling-off period to allow tempers to cool.

Even so, it was Mr Sefcovic who came off best in Wednesday’s exchanges, with a very practical-sounding solution to the problem of moving livestock and food across the border between Great Britain and Northern Ireland, which legally remains in the EU single market, Brexit or not. It has been rejected by the British, who mirror the EU’s “legal purism” with an obsessive “sovereignty purism” of their own – something that is equally silly in a world where the UK will need to make concessions in areas such as visas in order to win deals with the likes of the US and India, as well as to get Brexit done. For now, escalation – exacerbated by bad feeling over the supply of vaccines earlier this year – looks inevitable, as tends to happen in trade wars.

If there is one person who can perhaps push Mr Johnson along, it is Joe Biden: the New World coming to the rescue of the old once again. His devotion to the Good Friday Agreement is well-known and sincere, as is his scepticism about Brexit. This master negotiator will be armed with a simple message when he meets the prime minister this week, which is that if Brexit doesn’t get “done” to the satisfaction of the EU and Ireland, there will be no trade deal with the United States. If Mr Johnson doesn’t accept that simple reality, he won’t get a sausage out of the president.