What Rose brings to the Doctor’s life is completion. It’s completing a circle – he’s male, he’s alien, he’s a traveler. Between the two of them together they complement each other and discover each other. And are in love with each other – absolutely, unashamedly, unreservedly.

...The very word 'fiction' implies another world, literally a different place, whereas no one claims that a dedicated sportsman is escaping his life, or a chef or a nurse. But the poor writer - the sci-fi one especially - is seen as running away. Bollocks. This is real, for me, and it's tough, it's fun, it's practical, and it's very, very important.

Harriet Jones: Did you notice when they fart, if you'll pardon the word, it doesn't just smell like a fart, if you'll pardon the word, it's something else. What is it? It's more like, um... Rose Tyler: Bad breath. Harriet Jones: That's it! The Doctor: Calcium decay. Now that Narrows it down!.. Calcium phosphate. Organic calcium. Living calcium. Creatures made out of living calcium. What else - what else? Hyphenated surnames. Yes! That narrows it down to one planet! Raxacoricofallapatorius! Mickey Smith: [sarcastically] Oh yeah, great! We can write 'em a letter.

Doctor Who: You want weapons? We're in a library. Books are the best weapon in the world. This room's the greatest arsenal we could have. Arm yourself! (from Tooth and Claw in Season 2)

Fun, that's the word I keep on using. That's the word I worry about when other writer's scripts get too dark. Optimistic. Fun. And to be optimistic and have fun there's got to be a darkness there. I think that's a very British attitude.

[David Tennant's] Doctor has such humanity, he seems to understand us and he's very warm, so he's a comforting Doctor to be with, and he enables us to be slightly scarier than we had been.

Rose Tyler: Can't you come through properly? The Doctor: Then the whole thing would fracture. The two universes would collapse. Rose Tyler: So?