BRIGADIER: Let me tell you, sir, that I'm in full possession of all my faculties. After all, if I was suffering from amnesia, I'd be the first to know about it, wouldn't I?

BRIGADIER: Oh, I know how many beans make five, Doctor, and you don't have to be a Time Lord to cope with A level maths. It may come as a surprise to you, but I also happen to like teaching.