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.

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.

We have a plan to top it. And I do think our plan is devastating. We’ve practically reduced our cast to tears telling them the plan … we’re probably more excited that we’ve ever been about Sherlock.

To me, a 'brand' sounds evil.

It’s been a long time since Sherlock Holmes jumped off that roof - it’s time to reveal the truth about what happened between him and the pavement.

When writing comedy, you have to have the confidence to believe that there is only one type of relationship in the world, and we are all having it, that all men behave in the same way and so do all women.

Don't play games with me! You just killed someone I like, that is not a safe place to stand! I'm the Doctor, and you're in the biggest library in the Universe. Look me up.