Green Street Hooligans (2006)

Matt Buckner heads to London to take refuge with his married sister when he is unfairly expelled from Harvard. Befriended by the charming but dangerous Pete Dunhum, Matt falls into an underworld of football hooligans and is caught in a war between rival fight clubs, where gritty violence is a constant matter of life and death. In this extreme new world, Matt discovers his untapped inner strength, learns to fight and to stand up for himself, while forging the first real friendships of his life. When a secret about Matt's life back in the US emerges, friendships explode and loyalties are tested.

Official website: http://www.greenstreethooligans.com/