I don't want to think that the stories are finite; I want to feel that they can go on forever.

We're thrilled to have Maisie Williams joining us on Doctor Who. It's not possible to say too much about who or what she's playing, but she is going to challenge the Doctor in very unexpected ways. This time he might just be out of his depth, and we know Maisie is going to give him exactly the right sort of hell.

We're all stories, in the end.

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.

If you don't expect to like someone and then you do, that's an incredibly exciting moment.

Peter Capaldi, will always be Doctor Who. You retain the title forever. Ask your predecessors, they all think they're the real one. I've had Sunday lunch with Peter Davidson and David Tennant and they're eyeing each other like, 'It's me!

Sherlock Holmes becomes more human and more adept at fitting in with a lot of people, but he remains separate from the human race because he finds that a better place to observe that from. He stays on the mountain top because there, he can see clearly.