So much for the new, self-disciplined Boris Johnson who has banned gaffes and jokes during a public health crisis. The prime minister quipped to a private meeting of Conservative MPs that the UK’s success on vaccines was due to “greed” and “capitalism”. Although he quickly corrected himself, and aides claim he was speaking about the profit motive that drives commercial innovation, the damage was done.

The joker gets 0/10 for timing. His blunder came as he is in the middle of a charm offensive aimed at persuading his EU counterparts not to ban vaccine exports to the UK. He has now done the “offensive” without the “charm”; his Gordon Gekko moment will deepen the anger in Brussels about the UK’s vaccine policy.

“The UK and the US are not exporting, but we are exporting to the rest of the world,” one EU source told me. “Where is the fairness in that?” Indeed, the EU has exported more than 41 million doses to 33 countries, including about 10 million doses to the UK, from which nothing has gone the other way.

The European Commission’s latest plan is to restrict exports to countries with high vaccination rates and which do not export jabs. No prizes for guessing who that might affect: the UK, of course. For Ursula von der Leyen, the commission’s president, who is under mounting pressure over its woeful performance on vaccines, the move would offer a welcome distraction.

Wiser heads, including Germany’s Angela Merkel, are rightly urging caution, so the EU might stop short of a total ban. What UK ministers worry most about is losing supplies from the Pfizer-BioNTech plant in Belgium, which could disrupt the UK’s programme as people wait for their second dose of this vaccine. Johnson has offered to “go Dutch” by sharing with the EU the products from AstraZeneca’s plant in the Netherlands.

The good news for Johnson is that the EU’s performance is changing attitudes in Britain in a way he will welcome. A new Ipsos Mori poll for the EU-UK Forum, which promotes dialogue between the two sides, shows that two-thirds of people who voted Remain in 2016 think the UK has handled its vaccination programme better than the EU has.

What Mori calls the “halo effect” of the UK’s vaccine rollout could help the Tories in the 6 May local authority and mayoral elections; the party has already seen a bounce among older voters who, of course, were among the first to get the jab.

However, Johnson could squander this boost if he handles the dispute with the EU badly. If Brussels goes nuclear, he might be tempted to retaliate, but he should hold the moral high ground and avoid tit-for-tat vaccine nationalism. The UK is ahead in the race and a free-for-all, as well as being a terrible advert for Global Britain, would jeopardise its strong position.

Since the end of the transitional period, the UK and EU have quickly locked horns on two highly sensitive issues involving life and death – coronavirus vaccines and Northern Ireland. This sends an ominous signal about their future relationship. But with goodwill and flexibility on both sides, technical solutions could make the Northern Ireland Protocol workable, and end the threat to the fragile peace process.

Both sides need to move on from Brexit for the sake of their citizens. But they can’t, or at least don’t want to yet. The EU is struggling to come to terms with the UK’s departure. Elections in Germany and France in the next 13 months are uppermost in Brussels minds and encourage leaders to play hardball with the pesky UK and its populist prime minister, whose vaccine triumph rubs salt in the Brexit wounds.

A perpetual state of war would inflict damage on both sides; there would be no winners, only losers.