I had a guitar when I was 6 or 7, a plastic guitar with the Beatles' faces on it. It would be a collector's item now. It would fetch a hefty sum, I imagine.

When you play a character that is so emotionally closed there are times when you ask yourself if you are doing enough and if it's reading. That is where you have a director, who is the barometer of what you are doing.

I have three kids who like Harry Potter so I was sort of aware of it. You can't really move from it: it's on buses, in stores, it's everywhere. One of my kids has read the books; the other two are too small but they like the movies.

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.

To be honest, Im a little tired of playing bad guys. I long to do a comedy. But it was fun knocking Indiana Jones around.

I was brought up by my mother and my two sisters, although they're older than me and fled the nest very young, so I was technically raised as an only child, but I was very much loved.

Whats fascinating is that when you write a script, its almost a stream of consciousness. You have an idea that it means something, but youre not always sure what. Then when you get on the set, the actors teach you.