Britain will ask sport's top court to examine its lifetime Olympic ban for drug cheats after the World Anti-Doping Agency questioned the legality of the rule.

The British Olympic Association's by-law has come under pressure since the Court of Arbitration for Sport threw out an IOC rule, barring athletes who have received drug bans of more than six months from competing in the next Olympics.

The BOA ignored a letter from WADA last month questioning the legality of its rule and a second letter was received this week from the Montreal-based organisation setting out the legal reasons for its opposition.

Following the second letter, the BOA decided to ask CAS for a binding decision on the validity of the rule.

"The BOA has received correspondence from the World Anti-Doping Association which confirms that it believes the BOA eligibility by-law is non-compliant with the World Anti-Doping Code," BOA chairman Colin Moynihan said. "Of course, the BOA strongly disagrees."

Moynihan added that the BOA is seeking a CAS hearing to "vigorously defend the interests of clean athletes" and "bring clarity and closure to this issue".

WADA President John Fahey said in a statement to the Associated Press that his body is not directly challenging Britain's by-law at CAS, but that the letters sent to the BOA suggested that they "may wish to have its by-law tested by an appropriate tribunal".

Fahey said the BOA is yet to inform him of its decision to go to CAS and stressed that "no other steps have been taken by WADA".

But Fahey said WADA's executives will assess at a meeting this weekend whether Britain is complying with its code - a requirement of being part of the Olympic movement. It is just eight months until London stages the Olympics.

Since the BOA rule on lifetime Olympic bans was introduced in 1992, it has been applied 32 times and successfully overturned 29 times on appeal for "mitigating circumstances".

Among British athletes covered by the ban are sprinter Dwain Chambers, the former European 100-metre champion who served a two-year ban in the BALCO scandal and cyclist David Millar. If the rule is nullified, they would become eligible to compete in their home Olympics next year in London.

"It is a remarkable challenge from WADA in the absence of any challenge from a British athlete," Moynihan said.

The BOA announcement came a day after Moynihan accused WADA of failing to catch the world's biggest drug cheats and dragging the doping fight into a "dark age".

He called for an independent review of WADA, which was set up 10 years ago to coordinate the international fight against doping in sports.

Moynihan said only 59 of the world's 204 national Olympic committees are in compliance with WADA's anti-doping code, and that law-enforcement agencies - not WADA - were responsible for breaking up major doping rings and prosecuting cases such as the BALCO scandal.

Rob Harris
AP