Never been to London to be fair, however you do see some characters on British public transport.
In Birmingham once, Boxing Day 2006-ish, I got on a bus to a round of applause from a drunk middle aged Irishman, he then shouted "finally, it's not an African"

Also saw a lad go mad at a white boy for wearing Timberland shoes (lynching tree logo or something or other) once as I was going through Aston on a bus. Come to think of it I have seen bloody loads of blatant racism where I live.