When I first started working at the BBC, in 2001, what struck me was not how most of the people in charge were from the same universities, or that it was assumed you were a ski enthusiast, or how casually people dropped the names of powerful people they knew. It was the uniformity of thinking. There were progressive people and conservative people, but they mostly subscribed to the groupthink of the elite.

Surveying the levels of anger, abuse and fractiousness in the upper levels of British society today, it feels like a very different country. The Daily Mail’s front page, attacking the Tory Brexit rebels and triggering an avalanche of threats and abuse, was just the latest example of a culture war inside the British elite that makes any remaining class resentment against them look mild.

You might say we’ve been here before – but not often. When Churchill had to browbeat his cabinet to go on fighting the Nazis during the Dunkirk crisis in May 1940, there was a strategic fissure, but it was containable within the high Tory monoculture he shared with opponents such as Lord Halifax. The cultural conflict depicted in the recent TV series Howards End – between action and reflectiveness among the English upper middle class – was also conducted civilly.

But what’s happening now is off the scale. I can’t remember a time in British politics when different wings of the Tory party wanted to destroy each other more than they wanted to destroy the left. I can’t remember this level of viciousness in the briefing and whispering campaigns politicians conduct against each other. It’s as if every minor issue has become framed around the existential issues.

And they are real. The first one is obvious: Brexit. Two generations of lawyers, bankers, accountants and corporate managers had become so moulded to the Lisbon treaty, the European court of justice and the commission that even now, 18 months after the referendum, some are struggling to get beyond the denial stage.

The second existential issue is the one in the Daily Mail’s strap heading: “the possibility of a Marxist in No 10”. Combining the government’s defeat on the Brexit process with the fear of a radical left government in 2018 was a stroke of genius by the Mail’s editor because it goes to the heart of the British elite’s internal civil war.

Brexit was supposed to make the rich popular again. It was the great rhetorical wheeze that would reunite the Boris Johnsons and the Rees-Moggs with the plebs amid a bonfire of regulations and a sick-inducing spasm of nationalist joy. Instead, because the elite has already lost control of Labour, it threatens to put in power a government that will switch off the great privatisation machine, save universal public health provision and empower workers to an extent that has not been imagined since the 1970s.

Because the Tories screwed up Brexit, and Yvette Cooper screwed up the Labour leadership election, and then Theresa May screwed up almost everything, the British elite is mad as hell, spitting fury, spleen and threats at itself like professional wrestlers. One is tempted to order a large tub of popcorn, except that countries have elites for a reason. In a dangerous world, nations divided by class have historically relied on the best-educated, richest and highest-trained people to think strategically on their behalf; not just the politicians, but the top lawyers, central bankers and civil servants. If they do that in times of crisis, then, as Orwell did in the second world war, you can forgive daft hats at Ascot and the crazy rigmarole of regimental dinners.

This year’s crop of hypersentimental war movies remind us of why elites are useful: Kenneth Branagh as the naval commander in Dunkirk, stoically managing the evacuation; Julian Wadham as General Montgomery in Churchill, showing the calm leadership qualities that made the real-life Monty a hero to many of his soldiers; Gary Oldman as Churchill in Darkest Hour.

This world of cigarette smoke, woollen tank tops and deference is living memory for older people, but seems so alien to the young that it can be readily fictionalised using a few conventions. The main convention is that the British elite never loses its cool.

But it has well and truly lost its cool in 2017 – and the repercussions are echoing across public life. Oppose the government and you’re a traitor. Support Labour and you’re a Marxist traitor. Defend progressive values and you’re a luvvie – formerly slang for people in theatre, transformed by the tabloids into slang for people who care about knowledge, reasoned argument and restraint. The denigration of expert opinion emerged as a theme of the Brexit campaign and it has intensified during the elite civil war, as the tabloids belittle the reputations of lawyers, central bankers, economists and anyone foreign.

Right now, to a global audience, Britain looks like a sitting duck for every external force that wishes to destabilise it. The current prime minister has lost control and former prime ministers are hiring themselves out to despotic regimes. Soon we will get the results of the FBI probe into Russian manipulation of the Brexit referendum, we will have even more egg on our collective face, and the elite will be even more angry with itself. It’s probably not obvious if you spend your days buried in the British newspapers, but nobody else in the world is suffering this level of elite cognitive dissonance. Not even in the US – because despite the catastrophe of Trump’s presidency, the military and corporate establishments have moved in to sack the crazies and the Russian spies and to protect Trump from reality – and vice versa – in a miasma of Big Mac fumes and cable TV.

As many of us will discover over the festive season, a simmering argument among a closed group of people usually ends in an explosion. I can’t see the Tory cabinet or the xenophobic tabloid editors being happy until some cathartic incident happens to put one faction in control. Unfortunately – as everyone in the cabinet knows – that means the Tories cannot go on ruling for much longer. What clears the air in a democracy is an election – and we need one as early as possible in 2018.