The Masque of Mandragora

SARAH JANE: Just how big is the TARDIS?

DOCTOR: Well, how big is ‘big’? ‘Relative dimensions’, you see, no constants. There are no measurements in infinity. You humans have got such limited little minds; I don’t know why I like you so much!

SARAH JANE: Because you have such good taste.

DOCTOR: That’s true, that’s very true.

— The Masque of Mandragora (1976)