When you see how people in the developing world react and how they use a camera, you realise how narcissistic we are and how the filming of ourselves and thinking that we're interesting enough to care about is odd.

When you look at almost every submarine movie, to some degree or another, there's this 'Moby Dick' element, this Ahab element to them.

I'm not particularly ethnically Scottish; I have one grandfather who is Scottish, although he's called Macdonald, and you don't get a lot more Scottish than that. The Scottish part of my family are from Skye, and I've always been very aware of that - always been very attracted to Scottish subject matter, I guess.

It's nice to stretch in different directions and use different muscles. You can get swallowed into Hollywood, where it's all about bums on seats and how commercial a film is.

The tradition has always been that in Roman films, the Romans are always British, and it's usually posh British: Laurence Olivier and his ilk. My take on all this was that it's a metaphor for empire and the end of empire.

If there's a principle really worth sticking up for, I'll go the whole way.

I've fallen out very badly with some of the subjects I've interviewed, because they see their lives a certain way; to step into a cinema and see your life depicted in another way can come as a terrible shock.

The only obligation you have as a film-maker is to tell your version of the truth and to use your film to illuminate reality. Whatever that means.

No man, no woman is without their flaws.