There have been cheats at the Olympics since the earliest days of the modern games. In 1904 the runner Fred Lorz won the marathon but was disqualified when it transpired his manager had driven him half the race in a car.

Other cheats have turned out to have hidden qualities that helped them succeed. In Berlin 1936 Dora Ratjen came fourth in the women’s high jump event. Nothing unusual about that you might say, but Dora was really Hermann and ‘she’ was actually a man!

The same ruse was used by a number of gender-bending athletes untilcompulsory sex-testing was introduced in 1964, although such tests have now been abandoned as undignified and humiliating.

In more recent years cheating athletes and their trainers have resorted to doping to improve sporting performance, and have provoked a crisis in sport with some of the biggest names in sport being disqualified,stripped of their medals, and even jailed for using illegal chemical substances such as steroids. The 2004 Athens Olympics saw more than 20 athletes disqualified from the games after testing positive for bannedsubstances.

Will we see even more scandals in Beijing 2008? It seems inevitable since a number of athletes have already been banned or withdrawn from the games before they even began.

But some sports figures have called for even harder measures to be taken against drug cheats. Ten-time Olympic medal winner Carl Lewis has called for doping to become a crime throughout the world.

"I would change the law. If you test positive, why can't it be illegal?" said Lewis.