Dougie Walker, the European 200 metres champion, was yesterday still protesting his innocence despite being named as the British athlete at the centre of the drugs controversy which has rocked the sport.

An out-of-competition urine sample taken from the 25-year-old Scotsman showed traces of the banned anabolic steroid nandrolone. "I have never taken any banned substance," Walker said. "I've never used steroids and will contest the findings."

He faces a two-year suspension and a permanent ban from the Olympic Games if he fails to convince a committee formed by British athletics officials that he has not committed a doping offence.

"Dougie is not guilty and we will appeal," said his coach Davie Gibson. "There's a scientific explanation to this and I fully expect him to be exonerated."

One of the theories behind Walker's defence is that he may have tested positive after taking the muscle supplement androstenedione, which contains an offshoot of nandrolone.

It has already caused controversy in the United States, where it is endorsed by Mark McGwire, the baseball player who hit a record 70 home runs last year.

A few mouse clicks is all it takes to search for McGwire and androstenedione on the Internet and find his bulging forearms jutting across the computer screen.

McGwire and "Andro" have become inseparable, linked on Internet sites and in health food stores across the US. "The product behind McGwire's 70 home runs," the ad says.

Doctors in the US fear that McGwire, wittingly or not, is driving a potentially hazardous boom in Andro sales.

But there is no mention that, while Andro is allowed in baseball, it is banned in every other sport as it contains an offshoot of nandrolone. Randy Barnes, the Olympic shot putt champion, was given a life ban last year when he tested positive for nandrolone after taking Andro. The tennis player Petr Korda also failed a drugs test at Wimbledon last year after taking the supplement.

Walker's case overshadowed the launch of UK Athletics, the sport's new governing body, at a glitzy ceremony in London yesterday attended by the Sports Minister Tony Banks. Ironically, Walker figured largely in a promotional video on his way to glory at last summer's European Championships.

The case is further complicated by the fact that Walker's offence allegedly took place while the liquidated British Athletic Federation was technically still in charge of the sport. Moorcroft said Walker would be tried under the rules of UK Athletics as long as both parties agreed.