The Robber Button

I have been asked again a few times about how we got the name for our Narrow Boat "The Robber Button" so here is the explination in video and transcript.

The video is from Blackadder 3; in the first episode, Dish and Dishonesty; this is the transcript:-

Edmund Blackadder: Sir Talbot represented the constituency of(Dunny-on-the-Wold, and, by an extraordinary stroke of luck, it is a rotten borough.
Prince George: Really! Is it! Well, lucky-lucky us. Lucky-lucky-luck. (as a chicken) Luck-luck-LAKK-LAKK-LAKK-LAKK-cluck-cluck-cluck-cluck- cluck-LAKK-LAKK-LAKK.
Edmund Blackadder: ...You don't know what a rotten borough is, do you, sir?
Prince George: No.
Edmund Blackadder: So what was the chicken impression in aid of?
Prince George: Well, I just didn't want to hurt your feelings. Erm, so, what is a robber button?
Edmund Blackadder: *Rotten borough*.
Prince George: Oh, yes, you're right.
Edmund Blackadder: A rotten borough, sir, is a constituency where the owner of the land corruptly controls the both the voters and the MP.
Prince George: Good, yes...and a robber button is...?
Edmund Blackadder: Could we leave that for a moment?