Sir Chris Hoy says the fight to keep sport clean could take a backwards step if the lifetime Olympic ban imposed on British drugs cheats is overturned.
British Olympic chiefs expect to lose their legal battle with the World Anti-Doping Agency (Wada) over the ban.
And that would allow the likes of sprinter Dwain Chambers, banned for two years in 2004, to compete in London.
"It will be sad if we have to fall in line with the rest of the world," said four-time Olympic champion Hoy.
Speaking at an event to promote National School Sport Week, he added: "I don't see anything wrong with having more stringent rules. I think it should be the rest of the world that's falling in line with our rules.
"If you are caught for taking drugs, then you will not be allowed to compete in the Olympic Games. That to me is a good incentive not to take drugs.
"If you take that away, are you taking a step back in the fight against drugs?"
The British Olympic Association (BOA) is locked in a legal battle with Wada over the right to continue imposing lifetime Olympic bans on British athletes who have served suspensions for taking performance-enhancing drugs.
The Court of Arbitration for Sport (Cas) is expected to rule next week.
If the BOA by-law is revoked, Chambers and cyclist David Millar would be eligible for London 2012 selection.
The BOA has gone to Cas to challenge a ruling from Wada that its by-law is not compliant with the Wada code and therefore unenforceable.
The by-law was introduced more than 20 years ago and has kept a number of British athletes out of past Olympics.
Its argument, which has found support among a number of high-profile current British athletes and the International Olympic Committee, says its requirement that athletes have clean drugs records is part of its selection criteria for any Olympic Games, meaning the lifetime ban is not an additional punishment.
London 2012 organising committee chairman Lord Coe reiterated his support for the BOA on Friday.
"My position on this is well known," he said. "I think it is right for sporting organisations to have the autonomy to decide who they want to see in their teams.
"But I'm not going to speculate because we don't know yet what the final decision is."
Last month, the BOA had expressed itself to be "cautiously optimistic" of winning the case.
However, leading sports lawyer Howard Jacobs - who helped American 400m runner LaShawn Merritt overturn his Olympic doping ban - later said he believed the BOA would end up on the "losing side".
Olympic 400m silver medallist Roger Black told BBC Radio 5 live: "I think it's a sad day because you have to accept that we will have people competing for our country who have knowingly tried to cheat other people."
Current world 400m champion Dai Greene believes tougher action is needed to deter doping.
He said: "I don't think Britain should lower their standards to come in line with the rest of the world. The standards aren't tough enough."
Darren Campbell, who had his 2003 World Championship 4x100m relay medal taken away - along with Christian Malcolm and Marlon Devonish - after anchor-leg runner Chambers tested positive six months later for the steroid THG, believes the rules were too inconsistent.
He said: "It's up to Wada to change the rules so we don't have to keep revisiting this all the time."
Malcolm has said he hopes Chambers is given a chance to compete at London. "He has served his time now," he said last month.
Athletes would still have to reach the Olympic qualifying standard to be considered for selection.
Chambers, 34, who served a two-year athletics ban after his positive test but has since competed at world and European championships, attempted to challenge the by-law in the High Court before the 2008 Beijing Olympics, but his case failed.
Millar, 35, who was banned from cycling for two years in 2004 after admitting to taking the blood-boosting drug EPO, has said he would not seek to overtun the BOA's lifetime ban.
British Cycling's performance director David Brailsford backs lifetime bans for pre-meditated drug cheats, but would certainly consider Millar if he was available for selection.
"My job is to pick the fastest team, the best team that can win that race in London," said Brailsford.
"It is not my job to decide if somebody is eligible or not."