Christopher Hampton: If you’ve read the book, you’ll know it’s all about these huge columns of refugees traveling north through France being attacked by German fighter planes and straffed, and it’s a ragged conflict between British retreating soldiers and the advancing Germans. We had all those things in the script.

It was a budget problem. They wanted to make the film for $30 million, because they felt all along it was a risky venture and so that was the obvious section to start weeding out.

So we thought we’d make a virtue of this by just having these three soldiers, sort of like the Wizard of Oz or something, in some phantasmagorical way, walking through these landscapes, and then suddenly arriving at this teeming hell. As we got closer to it, Joe [Wright, the director] said, You know, we could take all these various scenes and do them all in one shot. And then, we only have to have the thousand extras for one day.

And so it was. It was pretty nervewracking because we started rehearsing at six o’clock in the morning and then we started shooting about four in the afternoon. We got three takes done, the third of which was at the magic hour. And then we embarked on a fourth take in the middle of which the Steadicam operator fell over. The guy had been walking backwards and carrying this vast thing through the sand for all day. And it turns out the third take was the only one that was workable.

James McAvoy: It was a massive gamble. Joe really went out on a limb. But he had a crew and a cast and who -- with his helming and his rustling and corralling and his ability to galvanize people -- who made it happen. Filmmaking is a miracle of collaboration, and that one day was a microcosm of that experience. There were 1,800 people involved in it and any one of them could have screwed it up at any one time. [We did] three and a half takes, and two and a half times one of those people or more did screw it up. The fact that we got a take nobody screwed it up is incredible. It’s a testament to [Wright’s] audacity, his genius.

The question for me was, How do I maintain connection with all the technical marks I need to hit -- not just physically [but also] in terms of level, acting wise -- while still feeling the emotions of that moment. And you start to get overwhelmed with the emotion, you know, because it’s an incredibly moving day -- to do [scene like this] so massively, it doesn’t happen a lot. Also, you’ve got pressure riding on it, so it amplifies the emotion. And you start to get a bit overwhelmed. Then you realize that’s you commenting on it, it’s not you living it -- it’s not probably the way every soldier felt, and it’s not necessarily the way that that soldier should feel. So you have to detach yourself quite a bit, otherwise you’re the actor going, “Haaah, it’s so sad and scary -- scary and horrible...” Which, of course, it is. But that should be the reaction of the person watching it, and, indeed, I let myself feel that when I was watching it two days later, and the rest of the crew as well -- we were all a mess together. Not to say actors’ jobs are in any way like solders’ jobs, because they’re not -- but there’s a detachment that you have to try and achieve in either of them, otherwise a logistical nightmare of a scene like that would fail because actors wanted to feel it.

(Technorati tags: Atonement, Dunkirk, James McAvoy, Christopher Hampton)