IT was a moment of panic in Brussels.

As the political pressure mounted on vaccine supplies, Ursula von der Leyen pulled the post-Brexit emergency chord. Unthinkingly.

Time moved quickly and, in a midnight tweet, the European Commission President reversed ferret, to use a journalistic phrase, and got the post-Brexit train moving again.

Friday’s late-night drama proved, if any proof were needed, just how sensitive the issue of the Northern Irish border is.

Yesterday, the language in the “vaccine war” hotted up. German MEP Peter Liese warned of a vaccine “trade war” while Andrej Plenković, Croatia’s Prime Minister, has spoken of how vaccine diplomacy turning into “vaccine hijacking”.

As expected, Brussels, enraged by the prospect of AstraZeneca not supplying the millions of vaccine jags it had contractually promised, triggered the mechanism that would allow a blocking of Europe-made vaccines to countries outwith the EU, which now, of course, includes us.

As the vaccine rollout zips along nicely in post-Brexit Britain, where 10%-plus of citizens have been inoculated, the rate on the continent is below 2%.

READ MORE: Article 16 Northern Ireland: EU ends threat to override NI Brexit deal in bid to control vaccine exports

Politicians across the 27 member states are understandably coming under pressure not least in Germany, Holland and France, where elections are in the pipeline. Sabres are duly being rattled.

Is it coincidence that Emmanuel Macron - facing right-winger Marine Le Pen rising in the polls - said this morning that Britain had to choose which side of the Atlantic its loyalty lay. “Half-friends,” the French President suggested, “is not a concept.”

He added: “What politics does Great Britain wish to choose? It cannot be the best ally of the US, the best ally of the EU and the new Singapore...It has to choose a model.”

Mr Macron is fighting hard to avoid another national lockdown in France, where on Friday 820 new deaths were reported, taking the total to 75,620. At present more than 27,000 people are in hospital with Covid-19, including more than 3,000 in intensive care.

As infection rates stay high, the French Government announced from Sunday that all but essential travel from outwith the EU would be banned and testing requirements inside the bloc would be tightened.

With voters sharpening their pencils ahead of forthcoming ballots, it is understandable how well governing parties have done in getting vaccines in people’s arms will be a significant factor in who gains power.

And, of course, post-Brexit, it will horrify Euro chiefs in Brussels fearing political contagion that outwith the EU Britain was doing so much better on a key issue than those 27 member states remaining within it.

The European Commission’s rash action managed to unite London, Belfast and Dublin in their outrage as it was carried out without consultation.

All those late nights and early mornings of tortuous negotiations to preserve the spirit of the Good Friday Agreement and keep an open border between Northern Ireland and the Irish Republic were swept away in just a few hours of panic in the Belgian capital.

Having raised the prospect of an export ban on vaccine exports from Europe, the EU then spotted how Northern Ireland, within the EU for the movement of goods, could become a back-door to Britain and so triggered an emergency clause in the Northern Ireland Protocol, Article 16, to suspend part of the UK-EU trade deal and reintroduce checks at the border with the Republic.

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Ironically, with the initial delay in goods getting to Northern Ireland post January 1 leading to Unionist politicians calling for the UK Government to invoke Article 16, it was not London but Brussels that did it.

Arlene Foster, the DUP leader and FM, was enraged and branded the EU’s move as an “incredible act of hostility”. Micheal Martin, the Irish Prime Minister, was also said to have been incensed at the Commission’s move. Needless to say, the debacle has led Ms Foster to repeat calls for Boris Johnson to scrap the protocol.

Meanwhile, in Brussels sources were accepting there had been a “misjudgement”. Another candidate for the understatement of the year award.

However, in what can be regarded as a positive silver lining, behind the scenes it was the UK Government which was diplomatically trying to keep the temperature down as the Prime Minister telephoned Ms von der Leyen to gently point out the potential impact of reinstituting a hard border in Northern Ireland.

As the penny dropped, around midnight, the European Commission President tweeted the U-turn, saying the UK and EU had "agreed on the principle there should not be restrictions on the export of vaccines by companies where they are fulfilling contractual responsibilities".

She added the volteface came about after "constructive talks" with Mr Johnson in which he had expressed "grave concerns" about the EU’s move; to put it mildly.

In their conversation, there may also have been a sensible emphasis against vaccine nationalism and that Covid-19 does not respect borders.

That is, if the virus is allowed to rage in one country, it will have the opportunity to shift its shape and become more resistant to vaccines being rolled out in another. We are, to use a hackneyed phrase, all in this together and will only get out of it together.

Julian Lewis, the former Northern Ireland Secretary, succinctly summed up Brussels’ rash action on the triggering of Article 16 by saying it had “cocked up big time”.

This morning, the Euro chiefs are licking their political wounds while the likes of Mr Macron, facing forthcoming elections, are hoping electors have short memories; of course, they don’t.

Life, post-Brexit, is throwing up a few surprises. It will doubtless throw up a few more.