The Doctor and Borusa in “The Invasion of Time”

I've kept you waiting, chancellor.

I'm quite comfortable, thank you.

Good. [Borusa hands him his newspaper] I had nothing to do with this, I promise you. Chancellor, you know about the rod of Rassilon.

Yes.

And you know about the sash of Rassilon.

Yes.

And especially, you know about the great key.

Yes.

Therefore, it would be very bad for us if you were to fall into the hands of the Sontarans. No breeding, you see.

It's not just a question of breeding, surely?

Oh, but it is, it is, I assure you, chancellor, it is. They're a cloned species, you see. They can multiply at the rate of a million every four minutes. Shall we go?

I think so.

Good.