I can say with pride verging on smugness that I've got two very successful shows that assume their audience is very smart.

I can't see what's wrong about assuming intelligence in your audience and what's bad news about being rewarded for assuming that.

Hitler: Thank you, whoever you are. I think you just saved my life. The Doctor: Believe me... It was an accident.

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!

I hope I won't become hated by geeks everywhere, but I don't really know comic books all that well.

River Song: Right, I have questions. But number one is this: what in the name of sanity have you got on your head? The Doctor: It's a fez. I wear a fez now. Fezzes are cool.

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.