At the 1997 World Championships in Athens, Richardson quickly ran the anchor leg for Great Britain in the 4x400m relay, winning the silver medal. His unofficial split time was 43.5. On the 7th January 2010 it was announced that Great Britain's 1997 World Championship 4x400m relay team are to be awarded the gold medal they were beaten to by a U.S. team which included Antonio Pettigrew, who admitted in 2008 to using performance-enhancing drugs.