There is a big, big hole in Ursula von der Leyen’s strategy of threatening to ban exports of the Pfizer vaccine to Britain unless Britain hands over shots of UK-made AstraZeneca vaccine to make up for a shortfall in EU-made supplies. Well, several holes perhaps – not least that EU member states have done their utmost to undermine public confidence in the AstraZeneca vaccine, with the result that millions of doses have sat unused in fridges. What is the point in extracting AstraZeneca vaccines from Britain if they, too, are left to languish in fridges while Emmanuel Macron, Angela Merkel and others put people off accepting the vaccine?

But the big hole that I meant was that one of the vital ingredients of the Pfizer vaccine – lipids – are made at a Croda International plant in South Yorkshire. If the EU really were to block exports of the Pfizer vaccine to Britain, Britain could impose a retaliatory ban on the export of lipids to the EU, preventing the manufacture of any vaccine at all. Pfizer, indeed, has warned the European Commission on this point.

How tempting it would be for the government to issue a counter-threat to do just this. You dare try to stop Pfizer sending us its vaccine and we’ll choke off production altogether, and no-one will get any. That would be, though, foolish. It is often said there are no winners in a trade war but in this case there would be a very clear winner: Sars-CoV-2, the virus which causes Covid-19. The UK government has a far better option: the Prime Minister should come out and tell the world that while the EU might be threatening petty vaccine nationalism, the UK will do no such thing, and will uphold the free movement of vaccines and their ingredients – and, indeed, all other products and components which flow across the borders.

To do so would send a very powerful signal to pharmaceutical companies, and indeed all other manufacturers: that Britain is a safe place to base your manufacturing. So long as you are not trying to supply the world with illegal drugs or sell weapons to malignant regimes, we will never try to ban exports or intervene in trade for political purposes. The government should then approach Pfizer – if it has not done so already – and invite it to shift its vaccine plant to Britain, finding a ready-made building or a site with guaranteed planning permission and maybe offering some financial incentive too.

The EU has come out badly enough from the vaccines fiasco as it is. It is not hard to imagine the ructions it would cause in the bloc if, in response to threats from von der Leyen, Pfizer’s Belgian plant shifted operations to Humberside or wherever. It would be a giant kick in the teeth for the EU’s native protectionism – and a huge boost for Britain’s reputation as a place to do business.