10 controversies that rocked the Olympics

Seoul 1988: Canadian Ben Johnson won the 100m in a world record time – then admitted using drugs

London 2012: China's badminton stars Yu Yang and Wang Xiaoli tried to manipulate the draw and were banned for not trying

Mexico City 1968: US sprinters Tommie Smith and John Carlos were banned for their political protest

Seoul 1988: South Korea boxer Park Si-Hun was pummelled by America's Roy Jones in 1988, but the judges awarded him gold

Munich 1972: Three seconds of added time gave the Soviet Union's basketball players time to net a winner against America

Athens 2004: Brazilian Vanderlei de Lima was leading the marathon when a defrocked priest intervened

Beijing 2008: Cuba's Angel Valodia Matos took his taekwondo disqualification badly – he kicked the ref in the face

Los Angeles 1984: US distance runner Mary Decker's Olympic hopes were ended when she tangled with Zola Budd

Montreal 1976: Soviet Union's Boris Onischenko fenced with an épée wired to score a hit without touching an opponent

Sydney 2000: US sprinter Marion Jones was the golden girl of the Games – but later admitted taking steroids