Why did you cast Colin Farrell in the title role?

A lot of young men wanted to play the role of Tommy Hart. I knew through my casting director that this movie "Tigerland" was out there, and that there was a whole bunch of young actors in it who were really interesting. I got into a screening and told the studio I'd solved our problem. I flew to Boston where Colin was making a movie, had dinner with him and knew we were in business.

At what point did you realise that he came from Dublin?

At that dinner really. I couldn't understand what he was saying at first because he talks so fast. What was so startling was that I just assumed from "Tigerland" that he was a kid from Texas. He had the accent nailed.

How did Bruce Willis take to this brash newcomer?

Bruce is a real pro. He's been at this for a while, he's been around the track and understands the game, and understands what it takes to succeed in the game. I think it was even more bold a move on his part because this movie is not called "McNamara's War" it's called "Hart's War". The character of Tommy Hart drives the film really.

The author of the original book based it on the experiences of his father, Nicholas Katzenbach. What was it like when he visited your set in the Czech Republic?

It was profound, knowing that Nicholas spent 27 months in a camp like that. For him to go to the camp and look around, and stand back because it was so real. It took him back 55 years.