Great Britain has lost its bronze medal to Canada after being disqualified over the second changeover in the 4x100m relay.
Dwain Chambers crossed the line third but the change between Harry Aikines-Aryeetey and James Ellington took place outside the designated box.
Canada was then awarded third place on appeal.
"It's heart-breaking," Aikines-Aryeetey said. "We found out when we were walking to the medal presentation."
Mo Farah is hailed as Britain's greatest ever athlete after repeating his Olympic success with a double victory at the World Championships.
He won two Olympic gold medals last year and has already won gold this year in the 10,000 metres but is he the greatest of all time?