Does an evangelical athlete take dope?: She was the epitome of squeaky clean, but even Diane Modahl failed a drugs test. Jim White wonders how

The expose of athletes as drug-taking cheats has become a summer commonplace, a familiar pattern which would not be complete without the instant vociferous denials of the miscreant on being caught out.

Thus we remember Ben Johnson, rattling with illegal substances, squealing that he was framed at the Seoul Olympics. Diego Maradona, a long-term client of the Medellin cartel, maintained that a hay-fever spray was responsible for his mad-eyed, camera-eating celebration after scoring a goal at this year's World Cup. And the British 400m runner David Jenkins, jailed six years ago for drug dealing, reckoned it was his technique, rather than his pharmaceutical intake, which gave the impression during competition in the Seventies that he was running on air.

But the reaction to the discovery that a sample of Diane Modahl's urine, taken during a random drugs sweep at a meeting in Lisbon in June, contained unnaturally high levels of testosterone, was something else. Throughout the sport, jaws dropped.

Athletics is rife with gossip about who takes what to make them run, jump or throw better. Usually when news breaks that one of their number has failed a dope test, but no names have yet been revealed, athletes draw up shortlists of the likely. According to Sebastian Coe, who was in Canada for the Commonwealth Games, Modahl's name was not in anyone's top 50 suspects, never mind their top ten.

At Sale Harriers, the club where Modahl has spent her entire career, the news that she was the first British woman athlete to test positive for illegal performance enhancers was greeted with stunned disbelief. 'I've known Diane since she was 11,' said Eric Hughes, Sale's women's team manager. 'The club is standing by Diane because we cannot accept she has done anything untoward. She has got where she is by hard work and dedication. There are plenty of youngsters at our club who look up to her and she would not risk it all by setting a bad example.'

'Drugs are just not in our vocabulary here,' added Alan Robertshaw, club secretary. 'If we knew any coach was involved, any athlete, they would be kicked out, no questions asked. Frankly, we're so stunned, we are having to stop and decide what we are going to do because at the moment we just don't know.'

Modahl does not bear the standard physical tell-tales of the over-testosteroned: she is neither hugely muscled, nor does her upper lip resemble Nigel Mansell's. Moreover, a born-again Christian - part of the evangelical wing of British athletics that maintains it is God rather than proscribed chemicals who gives them an extra spring down the track - Modahl has been a vociferous opponent of doping since she spent time training in East Germany in the Eighties. The night, a week ago, that she was informed of the test result, she cried solidly until six in the morning.

It would take a conspiracy theorist of some paranoia to be persuaded that all this is a front for a persistent cheat, constructed between the athlete, her colleagues and the sports administrators. But the fact remains she proved positive: yesterday morning her pathetic expectation that the back-up test would invalidate the first one was shattered.

So what is going on? How did an athlete with a 17-year reputation as the epitome of clean, fail a dope test? Alan Robertshaw theorised that she might have taken drugs accidentally. 'We try to educate our youngsters the moment they reach junior competition and face drug testing, tell them to be careful about what medication they can take. You can slip up. I could go up to my bathroom cabinet this moment and pick out five or six medicines which contain elements that are proscribed.'

But Dr Mike Turner, a former medical adviser to the British Olympic Association, said: 'Testosterone can be taken in tablet form, but it is not something that can be taken by mistake. It is simply not an ingredient of run-of-the-mill medicines.'

Modahl's secondary defence was that the testosterone had occured naturally in her body, a result of a medical condition. 'Some cancers produce a high level of testosterone,' said Dr Turner, 'but only in the latter stages. A woman in particular would be far too ill to run before that could happen. A cyst on the ovaries also produces testosterone, but not in sufficient quantities to affect a test.'

Testosterone does not in itself make you run faster. Like all anabolic steroids, it enables an athlete to work harder and recover more quickly. It is a short cut for the long periods of improvement required to become a champion. A snort of it before a competition would not turn you or me into Linford Christie; its only benefit is as part of a long- term co-ordinated regime.

'It has become the flavour-of-the-month drug recently,' said Dr Turner, 'mainly because those in the know mistakenly believe it is more difficult to detect.'

This season Diane Modahl entered a new training schedule prepared by her husband, the Norwegian sports guru Vincente Modahl. 'It is the first year he has coached me and the results are really beginning to speak for themselves,' she said after she won the European Cup 800m earlier this season. Her performances were not as dramatic as those of Vincente's former protege, the record-breaking Algerian runner Said Aouita, but she had moved up a notch or two in the world rankings. Vincente, who is also coach and manager of several other top athletes, none of whom has tested for drugs, has been by his wife's side since the test and has protested her innocence. He should know.

During last week's Commonwealth competition, the high jumper Steve Smith refused a drink handed to him by a stranger. 'You've got to the point where you don't know who to trust,' he said. Diane Modahl would agree with that.

Hamish McRae is on holiday.