Such horrible menial occupations in Victorian times
You notice a couple of times in the movie shots of workmen doing what can only be described as mind-numbing toil, like the men dropping those heavy weights to the ground repeatedly with the random pounding sound, or the topless men pushing some machine back and forth repeatedly in a regular rhythm. I can only imagine those were prisoners doing that, because I can't imagine anyone choosing to do that kind of horrible, repetitive numbing work voluntarily.