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

The British Olympic Association's bylaw 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 organization 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 bylaw is noncompliant 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 in order to "vigorously defend the interests of clean athletes" and "bring clarity and closure to this issue."

WADA President John Fahey said that his body is not directly challenging Britain's bylaw at CAS, but that the letters sent to the BOA suggested that they "may wish to have its bylaw 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 he said WADA will assess whether Britain is complying with its code, a requirement of being part of the Olympic movement.