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."
Team GB loses its bronze medal in the 4x100m men's final for an illegal changeover.
Usain Bolt and the Jamaica relay team won the 4x100m gold in Moscow, with the 100m champion finishing ahead of US rival Justin Gatlin in the final leg.
Great Britain wins bronze in the men's 4x100m final in the World Athletics Championships in Moscow, in a time of 37.80 seconds.
Usain Bolt and the Jamaica team have won gold in the men's 4x100m final in the World Athletics Championships in Moscow, in a time of 37.36 seconds.
Prime Minister David Cameron would "warmly welcome" a knighthood for Mo Farah after the athlete became the first Briton to win both long-distance titles at the Olympic and World Championships, The Sunday Times has reported.
The newspaper quoted Mr Cameron as saying: "The Olympic and world double-double is one of the great sporting achievements. If the honours committee were to recommend Mo for a knighthood, I would warmly welcome it.”
Farah completed the set with victory in the 5,000m at the Worlds in Moscow on Friday, after which he was widely proclaimed as Britain's finest ever athlete.
British and Northern Irish athletes have claimed five medals in the IAAF World Athletics Championships in Moscow so far, placing them seventh overall in the medal table.
- Mo Farah: Gold in the men's 10,000m
- Christine Ohuruogu: Gold in the women's 400m
- Mo Farah: Gold in the men's 5,000m
- Eilidh Child, Shana Cox, Margaret Adeoye and Christine Ohuruogu: Bronze in the women's 4x400m relay
- Tiffany Porter: Bronze in the women's 100m hurdles
Usain Bolt won his second gold medal of the World Athletics Championships cruising through the finish line to win the men's 200 metres.
The 100m champion won the race in 19.66 seconds for his third straight world title in the 200m.
British sprinter Adam Gemili has come fifth in the final of the 200m in the Athletics World Championships in Moscow.
Usain Bolt has won the gold medal in the 200m in the World Athletics Championships in Moscow, in a time of 19.66 secs.