An opponent of Brexit demonstrates outside Parliament in London on Nov. 20. (Andy Rain/EPA-EFE/Shutterstock)

LONDON — Prime Minister Theresa May basically called the 3 million Europeans living in Britain a bunch of queue jumpers. This has upset some people, because it is quite an insult here.

Understand that in Britain, jumping the queue is simply not done. Not by the British people, or their long-term guests.

East London, West London, posh or poor, public school or private, city or country — if there is a queue, you bloody well take your place.

Keep calm and carry on?

The whole reason the British — who are actually highly excitable — can keep calm is because there is a queue, and they know that if they stand at the back of it, they will eventually get to the front of it.

Order, people.

You know who cuts in line? In the British mind? Barbarians. Vikings. Foreigners.

It is true that sometimes a clueless tourist will jump the queue and then everyone in line, collectively, begins to get twitchy and invisibly upset, until, collectively, they decide not to actually say anything out loud to the tourist because that would be rude.

But they think it.

In a major speech to promote her Brexit deal to business leaders in the country on Monday, May promised, “It will no longer be the case that E.U. nationals, regardless of the skills or experience they have to offer, can jump the queue ahead of engineers from Sydney or software developers from Delhi.”

Egads. The Europeans didn’t like this at all.

Guy Verhofstadt, the Brexit coordinator for the European Parliament, went on Twitter to remind May that the 3 million E.U. citizens “living, working, contributing to UK communities didn’t ‘jump the queue’ and neither did UK nationals in Europe.”

E.U. citizens, be they Romanian astrophysicist or French maid, are allowed to live and work in Britain legally because they are members of the European Union, as are the British, who also have the right to live and work in other E.U. countries. This “freedom of movement” is one of the pillars of the E.U. and its precursor, which Britain joined in 1973.

Brexit will change all that — when Britain finally leaves the union sometime in 2021, or 2022, or whenever, depending on whom you believe. May has said that part of Brexit’s promise to “take back control” means taking control of Britain’s immigration policies.

“Free movement will end,” May told Parliament last week. “That is one of the key elements, I believe, of the vote in the referendum that we need to ensure we deliver for the British people.”

May has vowed to reduce overall immigration from hundreds of thousands annually to tens of thousands, and give preference to the “best and brightest” no matter where they’re from, over lower-skilled workers from Eastern Europe.

In the future, E.U. citizens will not be given any preference, she promised, over someone from India or Australia.

May’s line about jumping the queue was deemed deeply insulting, not only by the foreigners but by many Brits.

LBC radio host James O’Brien started trending on social media after a clip from his show Tuesday, in which he lambasted May for her remarks, went viral. By labeling Europeans queue jumpers, he said, May was characterizing them as “a cheat, as someone who is not to be trusted, as someone who will game the system, someone who is not quite playing with a straight bat, as someone who is a little bit iffy, a little bit dodgy. Why? Why? Because they’re foreigners.”

May did not misspeak. It was in copies of her printed speech. Political analysts assumed that she meant it, as a bit of red meat for hardcore Brexiteers.

Scottish First Minister Nicola Sturgeon wrote on Twitter, “Stopping EU citizens ‘jumping the queue’ — that the case for Brexit has been reduced to such a miserable and self defeating bottom line is depressing in the extreme.”

She called May’s line “really disgraceful.”

Layla Moran, a Liberal Democrat member of Parliament, said May must apologize.

The British press asked May’s official spokesman what the prime minister meant.

The spokesman replied, “We have always been clear of the important contribution which E.U. citizens make to our economy and to public services.

“The point the prime minister is making is that we wish to have a global system where people’s skills are the basis on which they are able to work in the U.K.”