"You see?" he said dropping his cigarette butt, "They even keep it on at weekends. Someone was bound to notice sooner or later. But the catflap ... ah, there is a very different matter. Invention, pure creative invention. It is a door within a door, you see."
Bonus Geek Points for the reference, this part added by myself. Original meme source for me, spotted in lolleeroberts place. *G*