The British Olympic Association (BOA) will take its fight to keep a lifetime ban for drugs cheats to the Court of Arbitration for Sport (Cas).
The BOA is challenging the World Anti-Doping Agency (Wada) policy that the ban is "non-compliant" with its code.
"We take a different view - we believe it is about our selection policy," said BOA chairman Lord Moynihan.
Sprinter Dwain Chambers, who has served a ban, could compete at the 2012 London Olympics if the BOA loses.
Both the BOA and Wada are looking for Cas to make a decision before the end of April 2012.
Moynihan told BBC Radio 5 live: "Selection policies differ from nation to nation. One of ours is that we will not select athletes who have knowingly taken drugs to cheat clean athletes for selection to Team GB and that has been in place for 19 years."
The BOA imposes a lifetime Olympic ban on any British athlete banned for more than six months for a doping offence - the only national Olympic committee to do so.
However, the policy contradicts Wada's global anti-doping code.
Lord Moynihan believes the majority of athletes support the BOA position.
He said: "We have asked the athletes, who are the most important people, and 90 to 95% after any Games - winter and summer - have supported that selection policy.
"We will continue to fight for our right to select clean athletes."
Two QCs, Lord David Pannick and Adam Lewis, will represent the BOA joined by a third lawyer, Tom Cassels of Baker & McKenzie. The lawyers are so supportive of the lifetime ban that they have agreed to represent the BOA for a fraction of their usual fees.
In October, Cas ruled that the International Olympic Committee's (IOC) own doping rule - which barred offenders who had received bans of longer than six months from competing in the next Olympic Games - was unenforceable.
That allowed Olympic 400m champion LaShawn Merritt to overturn a ban that prevented him from competing at the 2012 Games, enabling him to defend his title in London.
Moynihan added: "Wada's current position on this is that if you have a really serious drug offence - you've been taking drugs for years - and you get caught you will only get a two year ban.
"If you get the timing right immediately after a Games you will never miss an Olympic Games in the future.
"That to all of us in sport seems just an unsustainable position."
Moynihan is unhappy that the BOA has been forced to take the case to Cas.
He said: "The reality is it's Wada that have come after us and said 'we deem you to be non-compliant' so we are the reactors in this case.
"It's regretable we have got to take this step. To me it was completely wrong of Wada to mix up sanctions with our selection policy which has been in place longer than Wada has been in existence but that's their choice and we are defending our position."