The London 2012 chairman has poured scorn on sprinter Dwain Chambers' claims that it is almost impossible to reach the top in athletics without using drugs.

Chambers, who was banned for two years in February 2004 after testing positive for the banned steroid tetrahydrogestrinone (THG) the previous year, has put his track career on hold and is currently signed to NFL Europe team the Hamburg Sea Devils.

The International Association of Athletics Federations (IAAF), of which Coe is an influential member, have insisted that Chambers repay any prize money he earned while using THG through future earnings on the track, which the athlete claims is tantamount to being asked to "run for free".

He has also said that an athlete using drugs would have to be having "a very bad day" to be beaten by a clean athlete.

Double Olympic gold medallist Coe, the chairman of London 2012, is unimpressed by Chambers' attitude since returning from the ban and told the BBC's Inside Sport programme, due to be screened tomorrow:  "The IAAF have taken some money off him on the basis that he might come back, (but) he shouldn't be given that option.

"I've been saying for the last 25 or 30 years that if you systematically set out to cheat, then frankly you don't have a place in legitimate sport. He's probably in the right sport now, to be honest.

"We all accepted through gritted teeth that he could come back, but we all overlook the fact that it wasn't that long ago, drug-free, that the guy was running 9.87 (seconds) in Paris behind Tim Montgomery."

Coe added: "We have got throughout our history athletes who have got to the very highest level who have not (taken drugs)."

Olympic silver medallist Steve Cram echoed Coe's remarks and said: "When Dwain came back, people accepted that he had served his ban and he had paid his penalty.

"But once you decide to move away from the sport I don't have a lot of time for people who then stand on the sidelines and carp back on the sport.

"I wish he would just shut up about athletics.

"I genuinely believe there are people out there who can still perform to the very highest level and break world records without taking drugs."

Coe was also "depressed" by comments from Stephen Francis, the coach of joint 100 metres world record holder Asafa Powell, that if he was allowed to provide his athletes with drugs under the rules then he would do so.

Coe reaction to that: "This is a guy who is basically saying 'if I could use drugs within the rules, I would use them'.

"I think most coaches would walk away from their profession if that was the choice."

Chambers was the athlete used by London 2012 at a press conference in 2002 when they launched their campaign to bid for the Games.

Coe was not involved in the bid at that time