Movies

What really happened at Dunkirk

It’s as eerie as any Christopher Nolan film: A soldier rushes down narrow streets and onto a beach, where he finds line after line of other soldiers, staring at the sea.

That, more or less, was the scene in May 1940 in Dunkirk, the French beach town where Allied troops were driven by the Germans — a vision echoed in Nolan’s first film based on real events, “Dunkirk,” out Friday. To tell its story fully, the “Inception” director enlisted historian Joshua Levine.

‘If the British army had been destroyed or captured at Dunkirk, Britain would almost certainly have been forced to make peace with Hitler, and the country would have become, as [Winston] Churchill warned, a slave state.’

Together they traveled across Britain, speaking with survivors, most now in their 90s, about the miraculous evacuation of 338,000 soldiers by a volunteer fleet of small civilian boats.

It’s a story most Americans, and even some young Britishers, have never heard before.

But without the rescue at Dunkirk, Levine tells The Post, the world would be a very different place:

“If the British army had been destroyed or captured at Dunkirk, Britain would almost certainly have been forced to make peace with Hitler, and the country would have become, as [Winston] Churchill warned, a slave state,” says the author of “Dunkirk: The History Behind the Major Motion Picture” (Harper Collins, out now).

“I certainly wouldn’t be writing this now,” adds Levine, 47, “as all the Jews would have disappeared from Britain years ago. Freedom and tolerance and liberty would have evaporated, not just from Britain, but from Europe.”

From the diaries and memoirs he read — and the hundreds of hours of interviews he listened to — he found that the men trapped at Dunkirk for 10 days behaved in all sorts of ways.

The scene of the May 1940 evacuation of Allied troops in Dunkirk.ullstein bild via Getty Images

“One veteran described watching a man walking into the sea,” he recalls of a scene echoed in the film. “He described it as ‘suicide,’ but was he desperately trying to swim to England?”

He also heard of a soldier, “an ordinary working-class man,” who happened upon a restaurant and ordered Champagne — something he’d never had before — “and absolutely loved it.”

Levine says there were a few things in the script he suggested Nolan change, mostly dialogue that the historian thought didn’t fit the period.

“But he’d really done his homework,” Levine says. He says that he and Nolan discussed in detail the propaganda leaflets the Germans dropped onto the British soldiers.

“These leaflets showed a surprisingly accurate map and warned the British that they were surrounded by the Germans,” he says. “And the fact was that the soldiers welcomed the leaflets. They didn’t have maps of their own or toilet paper — and the leaflets came in handy as both.”

If nothing else, Levine says, the “Dunkirk” spirit lives on in his baby girl, born the day the film premiered in London. One of his producers, jokingly or not, suggested her middle name be Moonstone, after the boat that Mark Rylance’s character sails across the English Channel.

Levine and his fiancée decided on Peggy.

“Of the Dunkirk veterans I’ve met,” says Levine, “several had wives or sisters named Peggy — so I feel as though I’m honoring the period while giving my daughter a lovely name!”