Callum Priestley tested positive

Callum Priestley, the 21-year-old sprint hurdler, who won the 60m hurdles title at the British trials, has become the first athlete to fail a drug test after Dwain Chambers tested positive for Tetrahydrogestrinone in 2003.

Priestley was provisionally suspended from all competition and funding after his provided B sample tested positive for clenbuterol.

From Guardian.co.uk:

The UKA chief executive, Niels de Vos, said: "I am hugely disappointed that there has been a failed test. UKA continues to give 100% support to the work of UK Anti-Doping and we maintain our full commitment to drug-free sport."

Priestley's positive sample turned up following an out-of-competition test taken at a UKA training camp in South Africa in January. If found guilty he will face a two-year ban and a lifetime ban from competing as a British athlete in the Olympic Games.

Clenbuterol is on the World Anti-Doping Authority's banned substance list for its performance enhancing properties that include improved aerobic capacity and a faster metabolism that helps with weight loss. In 2008, the American swimmer Jessica Hardy was forced to withdraw from the US Olympic team after testing positive for the drug, while Poland's sprint canoeist Adam Seroczynski, who also tested positive, was disqualified from the K-2 1,000m event at the Beijing Olympic Games and subsequently banned from the sport for two years.

Clenbuterol is an ingredient in drugs prescribed to patients afflicted from chronic breathing disorders like asthma.