[on BBC's Sherlock] It's a rare challenge, both for the audience and an actor, to take part in something with this level of intelligence and wit. You have to really enjoy it. It's a form of mental and physical gymnastics.

I was always performing, doing silly voices. The teachers realized I could go one of two ways: be creative or destructive.

I've been very lucky at what's happened in my career to date, but playing something as far from me as possible is an ambition of mine - anything from a mutated baddy in a comic book action thriller, to a detective. If anything, I'd like Gary Oldman's career: he's the perfect example of it. I've love to have a really broad sweep of characters - to be able to do something edgy, surprising and unfashionable.

Looking for happiness is a sure way to sadness, I think. You have to take each moment as it comes.

I'm not one for doing the children's party version: "Hi, I'm a character in a movie and now I'm in reality!" I was doing the last shot of the film before reshoots outside their shop. I was starting my run into the frame and I thought, "You are literally ending where this began. The loop of serendipity's too much to not go in and acknowledge it." I just wanted to see the look on their faces.

Sometimes being away, on location, I feel like I'm away for much of my own life. I want to be better at staying connected.

I really cannot get over the generosity of our Tibetian teacher. He said, "Don't punish yourself. You're going to be a student at a university in the north of England. You need to have your experiences and have your fun, and not judge yourself. Don't live in guilt and regret."