God didn’t win World War II in Europe, and neither did the United States. The war against the Nazis was really won by a brilliant young gay man in the south of England – who until recently almost no one had even heard of.

Prejudice against gays wrote Alan Turing out of history, despite the fact that the only reason we’re not now speaking German and being enslaved by fascists is because of his once in a century genius. It turns out that what you don’t know can actually hurt you.

In the new film "The Imitation Game" (starring Dublin’s Alan Leech, 33, best known for his recurring role as Tom Branson in "Downton Abbey") we are given an unforgettable lesson in just how much we owe to a man most of us have never heard of.

Turing was the only one with the brilliance to break the German code-making machine called the Enigma. By doing so he allowed Churchill’s government to know every move the German Air Force and the U-boat fleet were making everywhere in the world from March 1940 onward. That top-secret information – which was used to plan for every major allied attack, including D Day – won the war.

"The Imitation Game" is on its firmest foot exploring the tension that existed between unfathomably gifted scientists like Turing and military leaders who did not have the training to understand what it was he was actually doing.

Not only was Turing fighting Nazism, he was also fighting military budgets, political leaders who did not understand how important his work was and even his own scientific colleagues, who were dazzled by how far ahead of them his thinking was.

To beat a machine you had to build another smarter machine that could anticipate it every time. That much seemed clear to Turing and that’s exactly what he set about doing.

But he didn’t just build a code breaking machine, as "The Imitation Game" shows us. He also built the world’s first computer.

That means we don’t just owe our freedom from tyranny on this earth to him, we can also thank him for every iPhone and every computer because he theorized and built the first one, making him the father of computer science.

In the film Leech plays Turing’s cautious confidant John Cairncross, who although not gay has a startling secret of his own under wraps that helps him identify with Turing.

Leech is increasingly coming to prominence for his eye-catching turns in peerless Academy Award bait like "The Imitation Game." Going eye-to-eye with the film’s co-stars Benedict Cumberbatch and Keira Knightley, Leech holds his own as potential leading man material in a production that is sure to catch Hollywood’s attention.

Because Turing was gay the British government didn’t build a statue on top of a 60-foot column in Trafalgar Square to acknowledge the world’s eternal debt to his genius. It was still illegal to be gay in 1940s England and it would remain so for roughly another 30 years. Gay men weren’t allowed to be heroes.

They also weren’t allowed to have happy endings. In this way "The Imitation Game" hedges its own bets by never allowing Turing (Cumberbatch) an onscreen romantic clinch, or even a flirtation. It’s one thing to hear that a gay man saved and transformed the civilized world; it’s quite another thing to be shown that he was, it seems.

Women too had to tailor their own ambitions and smarts to the prevailing prejudices. As the other most gifted scientist in the room, Knightley shows us how threatening she is to the men around her who try to manipulate and mold her. Being treated like outcasts, both she and Turing turn to each other.

Social prejudices change at a glacial pace, so we aren’t shown a lot of potentially illuminating story lines in the hope of not alienating a general audience. That’s why it would be a shame if people decide to skip this fine film because they are averse to seeing gay people portrayed on screen, since the film has already done so much to spare them their discomfort.

At some point even the most insuperable prejudice has to give way to sense, and "The Imitation Game" is another important step in that direction.

"The Imitation Game" opens in selected cities on November 28.