The lifetime Olympic ban for British athletes who test positive for drugs could be under threat after the IOC lost an important test case today.
US sprinter LaShawn Merritt has been cleared to run in the London 2012 Olympics after the Court of Arbitration for Sport declared an IOC ban on him taking part in the Games "invalid and unenforceable".
The IOC had ruled any athlete banned for six months or more for drugs must miss the next Games - but the British Olympic Association's (BOA) lifetime ban is even more draconian and now that could also be under threat.
The CAS decision gives hope to cyclist David Millar and sprinter Dwain Chambers, who have both served bans for drugs in the past, being able to be part of Team GB next year.
The CAS ruling states: "The IOC executive board's June 27, 2008 decision prohibiting athletes who have been suspended for more than six months for an anti-doping rule violation from participating in the next Olympic Games following the expiration of their suspension is invalid and unenforceable."
The CAS ruling stated that the IOC's only way of bringing in such a sanction was to have it agreed as part of the World Anti-Doping Code, to avoid claims of 'double jeopardy'. There appears to be little possibility of that happening however.
Olympics minister Hugh Robertson earlier this week insisted the BOA's lifetime ban can be maintained.
Robertson told Press Association Sport: "I absolutely support the BOA's stand on anti-doping. Athletes have to abide by the by-law which states there is a lifetime ban for drugs cheats.
"There is also the option to appeal under BOA's system, while there is not under the IOC's so it is a different case.
"I don't think this is the end of the road for the BOA by-law by any means."
Merritt had failed a drugs test for a substance contained in a male enhancement product and was given a 21-month ban.
Under the IOC's rule 45, he would have been prevented from defending his Olympic title at London 2012 even though he has completed his suspension and won a silver and a relay gold at the world athletics championships last month.
Merritt's case was supported by the United States Olympic Committee, whose chief executive Scott Blackmun insisted they remained committed to the fight against doping.
He said: "Like the IOC, we are in full support of clean competition and stringent anti-doping penalties. This decision does not diminish our commitment to the fight against doping, but rather ensures that athletes and National Olympic Committees have certainty as they prepare for London."
The IOC expressed disappointment at the judgement.
A statement said: "The IOC fully respects the Court of Arbitration for Sport and will of course abide by its judgment.
"The IOC has a zero tolerance against doping and has shown and continues to show its determination to catch cheats.
"We are therefore naturally disappointed since the measure was originally adopted to support the values that underpin the Olympic Movement and to protect the huge majority of athletes who compete fairly.
"The rule was in our view an efficient means to advance the fight against doping, and we were somewhat surprised by the judgment since we had taken an advisory opinion from CAS on the rule and been given a positive response.
"When the moment comes for the revision of the World Anti-Doping Code we will ensure that tougher sanctions, including such a rule, will be seriously considered."
UK Anti-Doping chief executive Andy Parkinson, who has previously called for the BOA to end their life ban, said: "UK Anti-Doping's position is well known on such matters.
"We believe it is appropriate that the decision from the Court of Arbitration for Sport strongly supports the authority of the World Anti-Doping Code, the internationally agreed set of rules.
"The global fight against doping in sport is a complex task and this ruling provides clarity for the sporting movement in the lead up to 2012."