The work carried out by those at Bletchley Park's top secret facility has previously been detailed in the 2001 film Enigma, but in that case the names were changed, and also notably the sexuality of its Turing surrogate. A year before, the Hollywood submarine drama U-571 provoked anger in Britain by rewriting history in favour of having Americans cracking the Enigma code. I suspect The Imitation Game is about as historically accurate as an episode of The Flintstones, but it's the first real attempt to convey the true genius of Turing and the importance of his work.

Any film dealing with a hyper-intelligent protagonist faces the difficulty of how to relate his genius to an audience that couldn't possibly wrap their small-in-comparison minds around it. Graham Moore's screenplay thankfully never attempts to delve into the intricacies of Turing's work; there are no ham-fisted attempts to relate its mechanics to us, because Turing couldn't even explain this to his co-workers, so far ahead of them was he intellectually.

Instead, the film plays like a Hammer Frankenstein movie, with Cumberbatch excelling as the Baron. It's testament to his acting abilities that, despite the similarities in their make-up (narcissistic geniuses who lived to solve puzzles), we never think of his portrayal of Sherlock Holmes while watching his turn as Turing.

The movie crosses back and forth between three chapters of Turing's life - his public school days, his time at Bletchley Park, and his arrest in 1951 - but never distractingly so. Indeed, it's a wise choice, as a chronological approach would have meant a deeply depressing final act focussed on his tragic end, not the way a figure like Turing should be remembered. Director Tyldum, who showed a great knack for moving a story along with pace in his Norwegian thriller Headhunters, continues in similar fashion, keeping the narrative trundling along at a whip-crack pace.

If the movie has a flaw, it's the way in which its narrative developments are too often conveyed through a series of Rube Goldberg-like plot contrivances and coincidences, and at times its intellectually superior protagonists behave like idiots for the sake of drama. But this is a movie in which plot takes a backseat to its fascinating central character, given the treatment he deserves by an actor at the top of his game. If the newly resurrected Hammer studios want a new Peter Cushing, they need look no further than Cumberbatch.