Football is the most popular sport, both in terms of participants and spectators, in London.[1] London has several of England's leading football clubs, and the city is home to thirteen professional clubs, several dozen semi-professional clubs and several hundred amateur clubs regulated by the London Football Association, Middlesex County Football Association, Surrey County Football Association and the Amateur Football Alliance.[2] Most London clubs are named after the district in which they play (or used to play), and share rivalries with each other.