Great info.
I worked in the East End for a few years building Murdoch's plant at
Wapping
We used to find old coins from the 1700s and lots of tobacco pipes while digging. One of my cockney coworkers had to climb down one of the sewers there and returned to report that "I saw this rat as big as a fucking cat. I threw a brick at it and it just stood there looking at me, as if to say "is that the best you've got?" "
Another guy I knew used to prospect for mercury in the sewers all over London. Kind of an urban gold prospector I guess. A very dirty and quite dangerous job but apparently worth it to him.
