THE IMITATION GAME: OSCAR'S 'BASED ON A TRUE STORY' CATCH UP II

What it is about Bletchley that drives the British crazy? Another Oscar nominee 'based on a true story', The Imitation Game provides yet another rejoinder to the British obsession with criticising Hollywood's playing with historical fact while ignoring British films which are every bit as 'economical with the 'actualite'. As I watched The Imitation Game, waiting for Kate Winslett to cycle through one of the shots, I recalled that in Enigma the traitor turned out to be a Pole. Except no Poles were allowed to work at Bletchley, even though the Poles had provided the Brits with an Enigma machine; they were banned because Johnny Foreigner can't be trusted to keep secrets like good old chappies from the right schools and Oxbridge.

The Imitation Game is structured as a thrilller: can Alan Turing and the Famous Five solve Hitler's puzzle in time to win the war? In order to make this thrilling, some truths need to be bent. Turing's inspiration, of looking for the words, like 'Heil Hitler' that appeared in every message was something that had been part of the decoding process since almost the beginning. And of course it wasn't simply a handful of people in one quonset hut watching while Turing built his computer; there were thousands of people engaged in the process at Bletchley Park.

But as the title implies, The Imitation Game isn't really a thriller. It's about Turing himself, as the ultimate enigma, and his own Imitation Game, his hidden life which saw him arrested for indecency in the early Fifties, and given drugs to chemically castrate him. Which is a story worth telling, and which has been told in a number of biographies. But the film traps itself in a morbid fascination with the appeal of victimhood, which forces it to twist Turing and his work to fit its framework of injustice.

There need to be obstacles in Turing's way, besides the obvious mechanical and mathematical ones. Hitler isn't villain enough for this film. The real villain has to be Alastair Denniston, transformed from a cryptographer himself who apparently ran his unit well, into a Colonel Blimp figure ignorant of the work his staff was doing and more obsessed with bringing down Turing than Hitler. Which is a shame, because the opening sparring between Charles Dance as Denniston and Benedict Cumberbatch as Turing is great, and could have been the basis of some dramatic tension without creating a cardboard villain.

In this film Turing has the double curse of being both gay and geek. Although Cumberbatch has a few Sherlock Holmes moments early in the movie, he has to be portrayed as being completely asocial (despite a dress sense which only disappears after he's drugged); the real Turing apparently could be quite gregarious. Although the film is sympathetic to Turing, it revels in stereotyping him: twice in the film Turing in effect commits treason: after the war by telling his whole story to the Javert-like detective who's convinced he's a spy, and during the war by hiding the fact that John Cairncross is a Soviet spy. Of course Cairncross, the infamous Fifth Man, never worked with Turing, ergo, Turing never was blackmailed by him, ergo Hollywood must have slipped this into the script when no noble Englishman was looking.

The conceit of the film, in turning Turing's paper titled The Imitation Game into a metaphor for his self, is a good one. He 'thinks differently', and a parallel is drawn between the man and his thinking machine. But in his naming the machine Christopher, after his lost early love, and his breakdown at the thought of losing what by movie's end is his only friend, takes him completely overboard. What's touching is the way Turing learns early to cover up his emotions, when the headmaster tell him his friend is dead, and he realises he never knew Christopher was even ill. Yet it's just as much English public school stiff upper lip as English closeted homosexuality. But just maybe the two are connected. But as young Turing says to Christopher, all speech is really in code, and in that is the core of what this film ought to have been about.

Turing was victimised, of course, but he also lived an active life (we never see a moment of gay affection in the entire movie; in fact its iconography is more concerned with the love story between Turing and Joan Clarke, played by Keira Knightly who looks as out of place in the 1940s as she does doing higher mathematics, although she does jut her jaw on cue). It was Turing who reported the burglary of his house to the police, not imagining it would lead to his own prosecution. And though the film says Turing committed suicide after finishing his court-ordered drug treatment, he in fact died a year afterwards, and there is some debate about whether his death were accidental rather than suicide.

It is right that Turing should be elevated to the position of a national hero, and that the prosecution and persecution of homosexuality should be condemned. The movie is strongest precisely at the moments Turing seems most human: when he realises immediately upon breaking the code that it cannot be used immediately to save lives. That one of the team has a sailor brother whose life is endangered that day is the kind of clunky fictional liberty one allows in a film, but it's a lazy way to add to dramatic tension. Still, there are liberties and there are liberties, as a 1940s bishop might have said to an actress, or indeed an actor. Bend the reality of Bletchley to make the chase of code-breaking more exciting, that's the way the game is played. But bend it to insist on Turing as a helpless victim, and reduce him to tears (it reminded me of Cumberbatch's Peter Guillam in Tinker Tailor Soldier Spy; he's left crying there too, as Guillam is given a gay backstory that seems to exist only for that teary payoff) and that's unfair, and indeed unheroic. The Imitation Game is structured and written (by Graham Moore, based on Andrew Hodges' book) cleverly, and directed by the Norwegian Morten Tyldum with the same visual panache and sense of movement that made Headhunters so enjoyable. Within its own terms works well; it's just a shame its terms are so limited by its agenda.