I think of myself as a writer with a sense of humour rather than a comedy writer. Happy to tell a story with lots of jokes in it - I wouldn't know how to do jokes without the story.

The trouble with a series as it gets older is it can feel like a tradition, and tradition is the enemy of suspense, and it's the enemy of comedy. It's the enemy of everything, really. So you have to shake it up.

The difference between a beautifully made failure and a beautifully made hit is who you've got playing the leads.

The universe is big, its vast and complicated, and ridiculous. And sometimes, very rarely, impossible things just happen and we call them miracles. And that's the theory. Nine hundred years, never seen one yet, but this would do me.

The way you get your script to the right people is that you put it in an envelope. It's easy. The difficult bit is writing something that is so good people will take a punt on a brand new writer.

Sherlock Holmes can be wise and funny. He wasn't, at the beginning. But later on, he's got a bantering relationship with loads of people. He's got a wisdom that he didn't have in the early stage. But he stays on the mountain top, and he will die up there. He's not going to change that.

You don't want to take over the universe. You wouldn't know what to do with it beyond shout at it.