Some excerpts from this morning's Andrew Marr Show, in which Benedict Cumberbatch talked to Marr about his acting roles - including that of Alan Turing in The Imitation Game (12A) which is on general release in the UK from 14th November 2014

Andrew Marr: .. during the Second World War vital work was done behind the scenes by those who decoded intelligence on German military plans. The mathematician Alan Turing was at the nerve-centre of the codebreaking operation at Bletchley Park. And a thrilling new film charts how he broke the German Enigma codes. Recently I asked the film's lead, Benedict Cumberbatch, before he announced his marriage engagement, if he agreed that Turing was one of the most important men of the 20th century.

Benedict Cumberbatch: I really do agree. The father of the modern computer age, a man of brilliant theoretical thinking. Somebody who thought philosophically about maths, and the application of machines beyond just his Universal Machine but into the world of full artificial intelligence.

Andrew Marr: And he broke the German codes, and it said at the end of this film that he ended the war two years before it would otherwise have ended and saved 14 million lives by doing that. What's the basis of truth in that?

Benedict Cumberbatch: I think huge. I think the rate the war was going and the amount of fatalities and waste of life was on the increase. It was a siege in this country at that time. What it meant by cracking the code was then being able to place all of the shipping movements, all of the planned attacks, and be able to span that out. Whether it be Luftwaffe raids, whether it would be a U-boat raid, and basically to be able to see on a map the reality of what the Germans were planning to do ahead of when they were going to do it. And then, of course you can't act on all that information without giving the game away that you've cracked the codes. But they then had this onerous task of feeding the information through certain channels to therefore, who knows, supply some people with the truth and keep some hidden. And as we now know, Coventry, which was rumoured at the time and until very recently rumoured to be known of, was definitely known about.

Andrew Marr: And they let it burn because the alternative would be letting the Germans ..

Benedict Cumberbatch: We let the entire city burn with thousands, hundreds of thousands of people dying in order to win the war. Which is just an unfathomable moral conundrum.

........

Andrew Marr: And Turing himself - now it has been said by some critics of this film, that the gayness has been glossed over in some way - that he's not gay enough in the film.

Benedict Cumberbatch: I don't quite know what that means, because to me, you know, his sexuality is very very clear in the film. We don't show him in bed with anybody - we don't show anyone who's heterosexual having a moment of sexual intimacy in the film.

...

Benedict Cumberbatch: The specific importance of his sexuality in both history and in the film is the fact that it was denied. That it was criminal - criminalised by that society at that time. And that he was punished, after saving the democracy and government that was in power by that democracy, for his identity. And I just hope that, you know, this film is about his achievements, about his life, it's about his loves as well, and it is about his sexuality. And it's a very very strong part of his identity ...

The Imitation Game (12A) will be in UK cinemas from 14th November. The film stars Benedict Cumberbatch as Alan Turing. One of the film's supporting actors, Keira Knightley, appeared as a guest on last night's Jonathan Ross Show (ITV1) -

Keira Knightley on The Jonathan Ross Show - 1st November 2014

Jonathan Ross: ... OK, so let's talk about The Imitation Game. Cos you've got two films out - one is out this Friday; one's out the week after. And this couldn't be a more different kind of film, could it?

Keira Knightley: No. It's about Alan Turing. So it's the story of the breaking of the Enigma Code, and Alan Turing and Bletchley Park. So yeah, it's very different and obviously with what happened to Alan Turing - I didn't know any of this. I sort of, I'd read articles about him about five years ago when they tried to get him a pardon. But he was a very brilliant mathematician who came up with theories that broke the Enigma Code in the Second World War, but was prosecuted for being gay and chemically castrated by the British government, which then led to his suicide. That doesn't give anything away. Well it does - kind of, doesn't it.

Jonathan Ross: But it doesn't really ..

Keira Knightley: It's kind of a story that's very much out there. So, yeah, it's very different from ...

Jonathan Ross: What's remarkable, though, when you think about it, cos you know that is shocking and it's a horrible story to hear happened. But it happened not that long ago in the grand scheme of things.

Keira Knightley: No, not that long ago.

Jonathan Ross: That's what's remarkable.

Keira Knightley: Yeah, and I think, you know, particularly because of the secrecy that's still around what happened, or well was around Bletchley Park until very recently, his place in history as far as one of the grandfathers of the Computer, as far as his place in the history of the Second World War, and in gay rights, you know, been has sort of lost. So I think everybody involved certainly wanted to be a part of trying to get that story to a wider public.

Jonathan Ross: It's a remarkable story from our comparatively recent history. But it's also a story which, I think, everyone should know - everyone should know about this man and what happened. ....

The Imitation Game - IMDb