The thing about drugs is that it [dealing] gives people an income to deal with, and it also gives people a compelling drama in their lives that they used to get from the office and the factory, and they're no longer there. What happens if you have everything in the hands of the state, particularly in the line of an authoritarian state, they just give people drugs to keep them doped up, to keep them passive.

We were looking for someone who could get the film [Filth] made at that kind of level, with the finance we wanted, and we spoke to a lot of people. When I met James [McAvoy] in the Soho Hotel with Jon Baird, the director, he looked about ten years old. I thought there's no way he's going to be a forty-year-old divorced alcoholic cop. I thought, really lovely guy, I'll let him and John talk and see if they get on.

When I started off with Trainspotting, it was the way the characters came to me. That's how they sounded to me. It seemed pretentious to sound any other way. I wasn't making any kind of political statement.

Ah suppose man, ah'm too much ay a perfectionist, ken? It's likesay, if things go a bit dodgy, ah jist cannae be bothered, y'know.

If you continue to transfer the wealth of the population of the planet to a very small amount of people, it becomes untenable at some point, a democracy, because people eventually will realize what's going on. You can only bulls - t people through kinds of media outlets for so long, and eventually you have to physically control them.

It's only now that I realize that behaviour always has a context and precedents, it's what you do rather than what you are, although we often never recognise that context or understand what these precedents are.

When you start off with your first book, people assume that you're like all the characters in the book - and it does complicate things, when you're being constantly bombarded with it, but you have to embrace it.