Christie, now 38, surely had nothing left to prove to the world. The real reason Christie was at the Sparkassen meeting in Dortmund in February was personal pride. Several of the runners he now coaches had made him a bet and, as ever, he did not fancy losing. Proteges such as Darren Campbell and Jamie Baulch had wagered that their mentor could no longer run 60m inside 6.60 seconds. If Christie lost, he would not be allowed to shave for six months. It was idle banter between the master and his pupils. Christie powered home in only fourth place -- but, crucially, in a time of 6.57.

Now, however, his decisionto compete looks misguided. After the race, he was drug tested by officials from the International Amateur Athletics Federation (IAAF), who found traces of a banned steroid called nandrolone.

Britain's most celebrated runner of modern times was suspended. A follow-up test produced the astonishing result that Christie was allegedly 100 times over the limit.

``If only Linford had retired when he said he would in 1997,'' said one athletics insider who has followed Christie's career. ``If he'd left it at that, his reputation would still be intact.''

As it is, he stands accused, for the third time in his brilliant career, of owing his speed to artificial rather than natural forces.

Twice before, he has cleared his name. Now, he must do so again. At the Seoul Olympics in 1988, the banned stimulant pseudoephedrine was found in his urine. Christie blamed it on ginseng tea he had drunk. Clearing him, the head of the Olympics medical commission said he had been ``given the benefit of the doubt''.

Soonafter, when 100m winner Ben Johnson lost his gold medal for failing a drugs test, Christie swapped his bronze medal for the silver. Christie had to defend his honour once more last year, this time in the High Court, when he sued the criminal-turned-writer John McVicar for libel for claiming he had taken performance-enhancing drugs. Another victory.

In between those two cases, drugs intruded on his life yet again when, in 1997, his younger brother Russell was stabbed to death in a street row over crack cocaine. The latest furore had been kept quiet since the February tests. When it finally broke last week, Christie protested his innocence, before adding: ``I hope the kids out there don't lose heart because I've always said you can get to the top without taking drugs.''

Much of the media expressed their horror that the gold medal-winning hero of the 1992 Barcelona Olympics had tested positive; one tabloid front page screamed ``Say it isn't so: Britain in shock as Linford fails two drug tests''. Butunpalatable as it may sound, the truth is that many athletes pop pills, inject illegal substances and down dubious ``health products'' and they do so with the aid of coaches, nutritionists and specialist sports doctors.

Just before the 1996 Olympics, the doctor to the British Olympic team, Dr Michael Turner, said, in his opinion, at least 75 per cent of all competitors in Atlanta had used performance-enhancing drugs in their run-up to the Games. He claimed that the authorities' drug-testing procedures were easily foiled. When athletes do test positive, they emphatically deny drug-taking and produce often-fantastic explanations for the findings. Often, these are accepted because champions are needed by their sport and increasingly, because the sport fears the prospect of protracted litigation.

When Diane Modahl successfully overturned her four-year ban for a positive drugs test, her High Court compensation claim bankrupted the British Athletics Federation. That claim is still on-going.

In this hiddenworld, taking drugs is not seen as cheating. ``Everybody takes something, whether that's a drug or a health additive. But 95 per cent of them do it mainly so they can get through training, recover from injury quickly, ... and only five per cent to actually get an advantage over their fellow competitors,'' explains one athletics insider.