Not Shakespeare

To sit in solemn silence in a dull, dark dock,
In a pestilential prison, with a life-long lock,
Awaiting the sensation of a short, sharp shock,
From a cheap and chippy chopper on a big black bloc

I apologize, I had always assumed for some reason this was Shakespeare. I was wrong. It is actually W. S. Gilbert. We used this line as an annunciation practice in theatre.