De Bruin - as Michelle Smith - won three Atlanta golds

Despite a rash of positive tests - and the discovery of illegal substances in swimers' bags - China has denied any systematic doping programme.

In recent years the country has taken steps to clean up its act, although there is clearly some way for them to go.

The most recent incident came as recently as July 2000 when world record holder Wu Yanyan tested positive for anabolic steroids.

She was immediately banned by her own federation, whose anti-drugs stance has now been praised by the Sydney Olympics organisers.

China's development as a swimming nation was as spectacular as its downfall.

Chinese swimming has risen and fallen more than once

The country won four swimming gold medals at the 1992 Olympics at Barcelona, and then took 12 of the 16 women's titles at the 1994 World Championships.

However their next major competition saw them fall to earth with a thud.

Improved testing methods at the 1994 Asian Games resulted in 11 Chinese athletes testing positive for dihydrotestosterone.

Seven swimmers were among those who had used the steroid, and the squad was so decimated that China won only one swimming gold in Atlanta.

Luggage find

The decline was only temporary and by 1998 China's women were rising back to the top - until four more positive tests and the discovery of Human Growth Hormone (HGH) in a leading swimmer's luggage before the world championships in Perth, Australia.

Subsequent Chinese times at the event were poor, adding to the weight of suspicion about the ebbs and flows of the country's swimming performances.

This time the Chinese authorities themselves decided to act, and they have promised blood tests for their Sydney Olympic team.

However the Olympic authorities also admitted before the games that there was still no way of testing for HGH - the substance found in luggage the last time the Chinese competed at a major tournament in Australia.

The jury is still out on Chinese swimming - but everyone will be watching them in Sydney.

Irish hero - and villain

China's brief mid-1990s lull coincided with the rise to stardom of Irish swimmer De Bruin, who competed in Atlanta as Michelle Smith.

She won three gold medals - three times as many as the Chinese swimmers put together - and became a hero back in her home country.

The incredible improvement in her performances raised suspicions at the time, and they were confirmed in early 1998.

Fina, world swimming's governing body, suspected that an out-of-competition had been tampered with.

The charge was denied by De Bruin, but Fina was undeterred and released details showing that the sample had "unequivocal signs of adulteration".

The Barcelona testing laboratory said it had an alcohol content "in no way compatible with human consumption", and that it was "compatible with physical manipulation".

The authorities suspected that alcohol had crudely been added to the sample in such large quantities to have made it impossible to be in the urine.

De Bruin appealed against her four-year ban, an ultimately unsuccessful and expensive exercise - and she will not be in Sydney to defend her titles in September.