Of all the football-mad cities in the world, few can compete with Manchester - home to two of the world's richest clubs, United and City. Football's global appeal cannot disguise the problems facing the game. Some fans say the sport is being ruined by financial greed, and racism is yet to be rooted out. Stephen Sackur speaks to former Manchester United and France star Patrice Evra. He has just done something most footballers never do by revealing his deep emotional scars. What made him do it?