OTTAWA — Thanks to a historical oversight by Hollywood, a long-ignored Canadian war hero is finally getting the honor that eluded him for 77 years.

Canada’s national parks service on Thursday is unveiling a memorial plaque in Montreal for Cmdr. J. Campbell Clouston, who is credited with savings tens of thousands of lives during the evacuation of Dunkirk in 1940, when retreating British and Allied troops were forced to flee by sea after the Nazi invasion of France.

Moviegoers who have been flocking since July to see the blockbuster film "Dunkirk," by writer-director Christopher Nolan, witness Clouston’s heroism in the role played by Sir Kenneth Branagh as the Royal Navy officer who oversaw the loading of ships for five days and five nights as piermaster of what was known as the Eastern Mole.

The mole was a narrow jetty that poked out almost a mile into the sea at Dunkirk. It was Clouston’s job to organize the orderly evacuation of petrified, exhausted soldiers who crowded four men abreast as they waited to be loaded into boats for their retreat to England. Adding to the confusion and desperation, they were periodically dive bombed by the Luftwaffe.

The only problem is that in the film, Branagh portrays a British officer with a distinctly English accent who is referred to as Commander Bolton. But there was no Bolton. The officer with the pivotal role in the evacuation was Clouston, a Canadian officer in Britain’s Royal Navy who was killed during the evacuation at age 39.

“I always felt he was one those great unknown heroes who had a real material impact on the success at Dunkirk,” said Serge Durflinger, a history professor at the University of Ottawa.

Clouston’s son, Dane, who was not yet 2 years old when his father died, saw the film this summer in England, where he lives, and was upset to see the depiction of his father not as a Canadian but as a Brit.

“I’m quite emotional about it all,” the 79-year-old retired naval officer and banker said. “Kenneth Branagh didn’t look anything like my father . . . My father was a chap with a megaphone wearing a duffel coat, not the smart great coat that Kenneth Branagh was wearing.” He was doubly disappointed because there was no mention of his father in the credits either.

Dane was so upset he wrote to the director and heard back from Emma Thomas, Nolan’s wife and producer of "Dunkirk," who explained that the Branagh character was simply a composite figure as were all the major roles in the film. Nolan himself told USA Today that he could not do justice to Clouston’s “incredible” story. “I am hopeful it will inspire people who are interested to look into the stories of the real people who were actually there.”

In Canada, the perceived slight got front-page attention. Canadians are sensitive to being ignored by Hollywood. When "Argo" was released a few years ago, there was an uproar over what was seen as the downplaying of Canada’s pivotal role in the rescue of six Americans during the 1979 Iran hostage crisis.

But Clouston never got much attention in Canada either. A member of a wealthy Montreal family, Clouston briefly attended McGill University before moving to Britain to join the Royal Navy in 1918, at the age of 17.

He rose in the ranks and married a British woman. When war broke out in 1939, Clouston was commanding a destroyer when he was tasked with helping the evacuation at Dunkirk. But because he never served with Royal Canadian Navy, Clouston’s story was largely ignored in his home country.

“In a way, he fell through the cracks,” said Jeffrey Street, a writer here who came across Clouston’s story when he worked on a CBC documentary about Dunkirk in 1999. “A lot of Canadian historians don’t write very much about Dunkirk.”

Street was struck by Clouston’s gallantry. “The conditions were appalling. There was the burning of the refineries. There would have been stench everywhere and he worked tirelessly for days,” says Street, who is working on a biography of Clouston.

After overseeing the evacuation for five straight days, Clouston returned to Dover to receive further orders. After staying overnight in England, he sailed back to Dunkirk to complete the evacuation of retreating French soldiers who were stuck on the beach. Clouston’s small boat was sunk and he was plunged into the frigid sea, where he tried to keep up the morale of his men as they awaited rescue. He died of hypothermia.

Thursday's ceremony, organized by Parks Canada, will be attended by Moray Clouston, Dane’s younger brother, who was born only months after his father’s death.

Street says he loved the film and wasn’t upset that it wasn’t historically accurate. “You don’t expect popular culture to teach history,” he said.

“And for all of the outrage that was expressed," Street says, "we have to give credit to Christopher Nolan that the film has raised more attention for Clouston than ever before.”

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