There is an ugly little word that keeps being used by some of the very worst people in Britain: quisling.

It is hard to understand why anybody thinks this term has a place in 21st century UK democratic politics. But a few do, maybe more.

We are, of course, talking about the name of a man, a very bad one at that. Vidkun Quisling was the puppet leader of Norway during the Nazi occupation of the Second World War. Even his initial, Q, has come to mean “collaborator”.

I remember the first time I saw this word dug out of history and spewed on to the internet. It was a decade or so ago, on what back then was still called Twitter. A few very zealous Scottish nationalists – cybernats, as they become known – took to calling the victims of their abuse quislings.

The insult was not just thrown at unionist opponents but at almost anybody, including non-partisan journalists, civil servants or academics who found themselves the crosshairs of key online influencers.

The hate did not stay online; it rarely does. There were even vandalisms – the single letter Q, for example, scrawled on the doors of unionist party offices in Aberdeen.

I wish it was just cybernats who abuse their foes as “quislings”. It is not. Some very online pro-UK activists, who had long preposterously equated mainstream independence supporters with Nazis, even invented a fake history in which a former leader of the SNP – the admittedly eccentric and politically irrelevant Arthur Donaldson – was a wannabe quisling. The dead do not sue.

Another brand of British nationalists soon adopted the Q-word. The radical Leave.EU group, for example, called Remainers quislings as it campaigned for its favoured hard Brexit.

Parties should expel people who use this kind of language. Sometimes they do, the SNP, for example, has (though not enough, say its critics).

But I would like us to stop and think about just how powerful a word quisling has become. The name of a collaborator from another country, from eight decades ago, resonates so strongly it is still in regular use as an insult. That is quite something.

I do not think many people from Britain really understand the idea of somebody working for a foreign force of occupation. Sure, the Germans took the Channel Islands. But we have no recent folk memory of being conquered.

Maybe that is why our hyper-partisan knuckleheads feel free to use words like quisling quite so lightly? Because they just do not “get” the real horrors of occupation?

Our rank patter about collaborators – whether over Brexit or independence – came just as Europe suffered its first war of conquest. It is nearly a decade since Vladimir Putin first seized chunks of Ukraine. It is more than 600 days since the Kremlin hardman launched a full-scale invasion of the country.

At one point Russia controlled more than a quarter of Ukraine. Even now, after counter-offensives, Putin’s armies hold something short of a fifth of the nation. Frontlines in recent months have not moved much. Millions of Ukrainians live under a foreign power.

That means, in practical terms, that Ukrainian authorities are wrestling with an issue profoundly unfamiliar to people in the UK: what should they do with people who co-operate with occupiers?

Shortly after the big invasion, the Ukrainian parliament passed a law on collaboration. It carries heavy penalties for those who support the occupiers. Just recently, for example, a police officer from a liberated town near Kharkiv was sentenced to 12 years. The 54-year-old had put on a Russian uniform and - Ukrainian secret service said - helped fabricate cases against local resistance.

Now I am not going to pretend to know any more than the bare bones of that story. I guess, though, this is what most of us would image “collaboration” looks like.

Ukrainian journalists last month compiled a list of more than 1500 Ukrainian nationals who were working with occupying authorities. There were cops, judges and local officials. But also teachers and utility workers.

And this is where there is some discussion in Ukraine about who exactly is a quisling, for who should bear criminal responsibility. Should teachers? Right now they might well fall foul of the law. Running a school or even a classroom is not a neutral act. Occupied Ukraine has been officially annexed by Russia, even if this is not recognised internationally. For educators on the ground annexation means using textbooks contaminated with Kremlin propaganda.

Having said that, teachers might not want to leave their students without an education. They might also, bluntly, need money and rations to survive. We are not talking about easy choices here.

Are utility workers collaborators? Well, again, as things stand in Ukraine, they might be considered so. Fixing power, water or gas systems, after all, can help the occupying regime, including militarily. It can also keep vulnerable people alive.

I do not want to second-guess the decisions of lawmakers, police officers, prosecutors and judges in Ukraine. Every case will have its own facts. But sometimes leniency will have merit.

Some our vacuous Scottish chat about quislings, some of our preoccupations with the Second World War, quite closely echo far more visceral and real narratives in Ukraine, about the past as much as the present.

The Kremlin likes to defame those resisting its invasion as Nazis. It does so by tapping into old stories of Ukrainians who sided with the Germans against the Soviets during the Second World War. And some Ukrainians did collaborate with the Germans. So, of course, did Joseph Stalin. It was the dictator's pact with Adolf Hitler that enabled him to grab what is now Western Ukraine in the first place.

Language matters. There are words so toxic they should only be used judiciously, whether we are talking about the UK or Ukraine. I think quisling is one of them. Remember, the Nazi stooge who gave has that word was shot for treason.