So Harry Potter came in and it is nice that I have kids of the right age. I took them to London and they walked around the set and met Harry Potter and that is thrilling.

Growing up in a particular neighborhood, growing up in a working-class family, not having much money, all of those things fire you and can give you an edge, can give you an anger.

My passion and energy get mistaken for anger.

I drank for about 25 years getting over the loss of my father and I took the anger out on myself. I did a good job at beating myself up at sometimes. I don't drink anymore but my alcoholic head occasionally says different. 'Nil By Mouth' was a love letter to my father because I needed to resolve some issues in order to be able to forgive him.

What other people think of me is none of my business.

Change is vital to any actor. If you keep playing lead after lead, you're really gonna dry up. Because all those vehicles wean you away from the truths of human behaviour.

And of course I've got kids of my own now, and they love me being in the Harry Potter films. I'm now part of a phenomenon. You become incredibly cool to your kids, and you get a young fan base. So you became the cool dad at school. You're suddenly hip.

Rather like Batman, I embody the themes of the movie which are the values of family, courage and compassion and a sense of right and wrong, good and bad and justice.

And of course I've got kids of my own now, and they love me being in the Harry Potter films. I'm now part of a phenomenon. You become incredibly cool to your kids, and you get a young fan base. So you became the cool dad at school. You're suddenly hip.

'Nil By Mouth' was a bit autobiographical, but as I always pointed out at the time, that's not my dad.