There are legends that beneath the city streets of London, in the far and quiet reaches of the London Underground's vast labyrinthine network of tunnels, a race of sub-humans lived.
Stories tell of a few people opting to live down there in the dank & dark spaces (much like Gollum) from the late nineteenth century, growing in number until a little nation existed.
Other stories tell of them starting to grow longer hair on their bodies (presumably for warmth) and stooping over (presumably from the small spaces they inhabit and poor nutrition). Some tales say that they died out in the twentieth century due to some kind of disease or infection that spread amongst them.
A film was made in the seventies that touched upon this story - starring Donald Pleasance - called "Raw Meat" or "Death Line".