IOC president Jacques Rogge has admitted that he is expecting positive cases of athletes using performance-enhancing drugs at London 2012.
Measures taken to catch drug-cheats include state-of-the-art laboratories and a 10% increase in the number of drugs tests compared to the last Olympic Games in Beijing in 2008.
Rogge told BBC Sport: ‘There have been positive cases in each Olympic games since we have started testing. To say there will be no positive cases would be naive and misleading. I hope it’s the case, but reality tells me that there may be positive cases.’
‘Everything that is humanly possible has been done in London to minimise doping. We hope that it will be the lowest possible number and we do everything we can to protect clean athletes.’
The IOC chief recently suffered a set-back in his fight against athletes found guilty of cheating, after Beijing Olympic champion LaShawn Merrit won an appeal in October against the International Olympic Committee who were attempting to block him from competing in London 2012.
Merrit was found guilty of doping in 2009 and subsequently served a two-year ban from athletics.
The Court of Arbitration for Sport (CAS) ruled that preventing the American from competing in the Olympics went beyond the Word Anti-Doping Agency sanctions of a maximum two-year ban and in essence would have been a second punishment for a single offence.