Creep (2004)

Creep is creepy. Set in the London Underground, a young woman gets locked in when the station she is at closes, and becomes hunted by an ugly, deformed, gollum-like creature - and you get to see plenty of him. He's twisted and animalistic, and parts of the film are extremely disturbing and gorey. There are some tortuous of this film that are unforgettable and difficult to watch - and if you take a look you'll see why.
http://www.youtube.com/watch?v=QZUzM_p6a1k