We seem to spend a lot of our time in very small spaces spouting a lot of dialogue very quickly.

I was always going to act, literally ever since I was tiny. In fact, I have Doctor Who to thank for that. I wanted to become an actor after being obsessed with Tom Baker, the fourth Doctor Who, in the 1970s. His was the definitive performance of all time in anything.

Back in 2005, when I was Christopher Eccleston, we saw one of the largest increases on record, of CO2 in the atmosphere. Unless we keep the rise in global temperature to under 2 degrees, by the time I'm Daniel Radcliffe or wee Jimmy Crankie, I won't be able to save the planet. I won't be here to help you -- well I might, but I'll be that bloke who won Any Dream Will Do.

When you're playing a real person there's a balance between playing the person in the script and playing the person as he was in life. You have to be respectful and true to who that person was, but at the same time tell the story in the film.

Twitter! It's like being stalked by committee!

I remember a conversation with my parents about who the people on the TV were, and learning they were actors and they acted out this story and just thinking that was the most fantastic notion, and that's what I want to do.

I've always been a geek and slightly awkward… slightly umm… I was never the cool kid at school.