IT’S hard to take all these WWII movies, as Brexit staggers towards its awkward, broken conclusion.

Before the end of 2017, we will have seen Their Finest (a romantic comedy about wartime filmmaking), two Churchill movies (played by Brian Cox and, in November, by Gary Oldman), and now Christopher Nolan’s Dunkirk. Ridley Scott’s Battle of Britain will land on us in 2018.

Yes, these movies often take 3-4 years to make, from proposal to release. But you’d have been a very dull cultural entrepreneur indeed to miss this boat. That is, the rise of an appetite for powerfully unifying British stories – whether provoked by the rise of Ukip and Euroscepticism, or the way that Unionists invoked post-war island unity against the disruption of Scots indy in 2014.

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One can imagine quite a few successful pitches to financiers across linen-covered tables in London and LA. These are surely only the first fruits of their well-lunched labours. Tin hats at the ready.

And what more powerfully unifying story than Dunkirk? The brave British soldiery trapped on a French beach, fired at from below and above, Spitfires desperately fending off the Stukas trying to bomb and strafe them. And then, answering Westminster’s call, the flotilla of Little Boats – coasters, launches, lighters, lifeboats, barges, tenders, trawlers, motor boats, cockle boats, pinnaces, fire floats, tugs, yachts … 700 volunteer vessels coming to ferry soldiers off the beach, either to bigger ships or all the way back across the channel.

The performance of One Direction’s Harry Styles in the Nolan movie is spraying celebrity sea-foam all over the media. But to cast the magnificent Mark Rylance as the master of one of those Little Boats is a serious assault on my otherwise robust defenses.

Deploying the same soft West-Country accent he used as Rooster in Jez Butterworth’s Jerusalem, or as the animated BFG, nobody conveys quiet civilian heroism quite like Rylance. In his tweed waistcoat and homespun leadership, he is the embodiment of the “Dunkirk spirit”.

Yet what is that “Dunkirk Spirit”, and to whose benefit is it currently being summoned? Pair it with “Brexit” in a websearch, and a roll call of Tory ministers deploying military metaphors stretches long and wide.

David Davis justifying an ill-prepared civil service, saying they “coped with World War Two – they can easily cope with this”. Boris Johnson warning the then French president “not to administer punishment beatings”. And a whole string of metaphors from Theresa May that vaunt the idea of Britain “standing alone”, in the face of subversion and interference from those dodgy Eurocrats.

Academics are marching forward to dispute the notion that Britain really “stood alone” for very long after 1940, when the fall of France to the Nazis triggered the Dunkirk evacuation. In that year alone, Canada, Australia, New Zealand, South Africa, Bahrain, Nepal, Newfoundland, Oman, and Samoa – meaning considerable chunks of the British Empire – had already declared war against Germany. And it was that empire’s supply routes and naval forces which also contributed to British resilience.

Historian Daniel Todman notes that official British propaganda after 1940 was at pains to “highlight overseas servicemen, praise European resistance movements and celebrate the successes of the Red Army”. Yet at the war’s end, says Todman, it suited UK governments to portray the country’s scale of achievement as singular and massive, as they lobbied the US for reconstruction aid and recompense.

“High time we told the world and blow our own trumpet”, Todman quotes from a civilian at the time. Britain, the historian continues, “has never stopped sounding it since”.

It’s a familiar worry from academics – that there are some fundamentally romantic misreadings of history that underpin the actions of Brexiteers. Delusions of grandeur are fatally damaging their ambitions and negotiations. And the idea of a “Dunkirk spirit” – involving a mass withdrawal from Europe, then a drawing on the resilience and inner strength of the nation alone – could be as damaging as any other delusion.

Luckily enough – and going by the stated intentions of the filmmakers themselves – this Dunkirk movie might easily resist requisition by Brexiteers looking for cultural weaponry.

In an interview with historian Joshua Levine, Christopher Nolan is at pains to say that the Dunkirk story is “not a victory, it’s not a battle. It’s an evacuation, a survival story … We have approached it from the point of view of the pure mechanics of survival, rather than the politics of the event”.

Nolan explicitly invites a comparison with the current migrant crisis in Europe – “the physics of extraordinary numbers of people trying to leave one country on boats and get to another country. Reality is insurmountable. And the overcrowding on those boats, with that human desire for survival”.

In an interview a few days ago, Mark Rylance pointedly made a comparison with Grenfell Tower: “We are all now so aware of civilian involvement, and civilian rescue services … I have a cousin who was a fireman in Grenfell, making decisions about who and who not to save, like many in the movie.”

The movie is made from three different timelines: three characters moving through land, sea and air. In this, Nolan is also staying consistent to the interests he’s pursued for years, through movies like Memento, Inception and Interstellar.

Nolan describes these interests as the “illusive nature of individual subjective experience describing objective reality. The film tries very strongly to leave space for the seemingly infinite number of experiences and stories” that could come from Dunkirk.

Strikingly, there is no mention of Germany or the Nazis in the movie at all – the focus is on the experience and methods of survival for the hundreds of thousands being evacuated.

So it would seem the filmmakers’ have been careful to ensure their epic can slip from the grasp of opportunistic, trouble-seeking Brexiteers. They’ve raised it to a universal level – a suspense tale about struggle and resourcefulness.

But if the Dunkirk film truly is a universal tale, then much else can be attached to it. As an image of a populace mobilising itself to act, the Little Ships of Dunkirk – chugging doughtily across the channel, responding to an existential crisis facing their fellow human beings – can barely be matched.

In fact, we do currently face an existential threat that is as bad as any war: our worsening climate crisis. A chunk of ice several times larger than Wales sheared off Antarctica this week, deeply alarming climatologists. And the western op-ed pages have been convulsed by an essay in New York Magazine, entitled “Uninhabitable Earth”. Its survey of the best climate research shows a planet heating up and choking off living conditions for hundreds, if not thousands of millions of humans.

“Where’s the bloody airforce?” is a cry heard plaintively in the movie. But when it comes to climate change, with transatlantic leaders failing us so miserably, we may have to start assuming that there is no-one flying down from on high to save us. Even if the elites do eventually get their act together (and environmentally, they’re not bad in Scotland), nothing should stop any of us adding our little boat to the flotilla. Act locally, think globally, as the Greens used to say.

I know a few great organisations – Transition Towns, Flatpack Democracy, Campfire Convention (and let me also suggest the one I’m involved in, The Alternative UK) – which are consciously all about triggering the power of local action. No one size fits all, and all steer alongside each other, heading towards an obvious horizon – which is a massive reduction in carbon emissions, before it’s too late.

If the “Dunkirk spirit” is about people rescuing themselves, and averting disaster, then it can be channelled in much better directions than the Union Jack-lined pockets of May, Johnson, Gove and Fox.

Dunkirk, directed by Christopher Nolan, is out next week in all cinemas.