The British Olympic Association (BOA) claim they would "vigorously defend" any legal challenge made by Dwain Chambers as he looks to overturn his Olympic ban.

The BOA's strong statement comes after Dick Pound, the former head of the World Anti-Doping Agency (WADA), said he believes Chambers could still compete at the Beijing Olympics, claiming the BOA were "on pretty shaky ground" in their decision to ban the sprinter under by-law 25.

The Association introduced the law in 1992, when Sir Arthur Gold, the then chairman, decided Britain should lead the way in the fight against drugs. Since then there have been 26 successful appeals against the ban, the last being Christine Ohuruogu's, but nobody has challenged the actual legality of the rule in the courts.

Chambers, who completed a two-year doping ban in 2005, is considering a legal challenge to the law, however, the BOA insist they would launch a fierce defence of the bylaw if Chambers chose to mount a challenge.

A BOA spokesman said: "First, as it stands Dwain Chambers is ineligible for selection for Team GB because he has committed a serious doping offence. Secondly, he is eligible to appeal if he wishes to and there are three grounds on which he could appeal. That the doping offence was minor, (there was) a finding of no fault or negligence on his part or there are significant mitigating circumstances in relation to the doping offence.

"Thirdly, we have not received any appeal from him. And finally, we will vigorously defend any case that comes to us which is taking on our anti-doping by-law."

However, as yet Chambers has not made any challenge - although if one was made it is expected to be based on the issue of the legality of the ruling rather than an appeal for clemency.

Although Pound, who stood down from his post at WADA in November, admits the legality of the BOA's ruling could well be tenuous.

"As a matter of law, I think the BOA would be on pretty shaky ground," he said. "If the BOA sought to deny me a place in the 2008 Olympic team on the basis solely of my earlier drugs offence, I would say that they don't have the power to do that. If you serve the penalty that was deemed appropriate - for whatever the offence was - you are entitled to be reintegrated into society.

"I've always felt it was fairly clear what the outcome (of a challenge) would be."

Chambers received a two-year ban after testing positive for tetrahydrogestrinone (THG) and becoming caught up in the Balco scandal, which involved the distribution of performance-enhancing drugs. As well as Chambers, the affair brought down the likes of Marion Jones and former world record holder Tim Montgomery.

Chambers returned to the sport in 2005 and was part of the victorious 4x100m squad at the European Championships before attempting to forge a career in American Football. The sprinter made another successful return to the track in February this year and will represent GB in the 60m at the World Indoor Championships in Valencia this weekend.

However, British officials did not want to choose the former world junior 100m record holder but his dominance at the trials in Sheffield last month forced the selectors' hands.