Drugs in Sport: Dwain Chambers, Britain's European 100 metres champion, has admitted testing positive for a banned new designer anabolic steroid but has blamed Victor Conte, the controversial nutritionist recommended to him by his coach, for the adverse finding which could wreck his career.

The 26-year-old confirmed yesterday's story he had tested positive for tetrahydrogestrinone (THG) but claimed he had been assured what he was taking was a supplement which did not contain any illegal substances.

Chambers's solicitor, Graham Shear, said in a statement that while in the US the athlete had been instructed by his trainer, Remi Korchemney, to use Conte of Balco Laboratories in California as his nutritionist.

"In August this year Dwain was tested out of competition in Germany. In early October he received notification that the A sample had tested positive for THG. Dwain had never heard of this substance and he immediately challenged Mr Conte on this finding and was categorically assured that all supplements he had been given were within the IAAF [International Association of Athletics Federations] rules."

The statement added Chambers had never been tempted by illegal methods of enhancing performance.

Chambers claimed over a year ago drug use in athletics added to the excitement of the sport. Speaking in an interview with the BBC conducted in September last year, Chambers said athletes often "took chances" with drugs to compete at the highest level.

In the interview, which was conducted shortly after Chambers had begun being coached by Korchemny, he said: "The 100 metres has always been branded as the blue-riband event and regardless of what people are doing or what they are taking it is the excitement that it brings . . . that keeps the sport standing on its feet."

Asked about the prevalence of drugs in sprinting he said: "It's difficult. It shows how tight the sport really is. If you want to be the best, people often take chances in order to get themselves where they feel they needed to be . . . If you want to be playing on a level playing field some people do . . . make those decisions (to take drugs) and it obviously puts the sport in a dampened cloud but at the same time you can't take away the excitement that it does bring."

Asked if the 100 metres was a clean event, Chambers was ambiguous. "Who knows? Who is going to know? At the end of the day all the athletes are out there and participating in it and as long as they're going out competing and taking the appropriate tests in and out of competitions and they come back negative then you can't really say nothing to it."

His defence echoes that of Kevin Toth, the US shot putt champion, and the only other athlete to have been publicly identified as having tested positive for THG. The defence that they did not know what they were taking will not save them as they are responsible for any substance they ingest.

Under the rules of UK Athletics, which will hear Chambers's case, the athlete faces a minimum two-year suspension if he is found guilty. That could be extended if the IAAF concludes that he was part of a conspiracy.