The Doctor and Ben in “The Power of the Daleks”

Now, Lesterson's fanatic. The Governor's jealous of his own position. What does that suggest to you?

Dunno. Hadn't thought about it. That all is not well with this colony. Add to that one Dalek!

Ben

Oh, blimey, you don't half make mountains, don't you? One Dalek?

[explaining] Yes! All that is needed to wipe out this entire colony.