Three-time Tour de France champion Chris Froome has called on the UCI and World Anti-Doping Agency (WADA) to end what he termed the "abuse" of the Therapeutic Use Exemption (TUE) system, which allows athletes to treat medical conditions using drugs that would otherwise be banned.
The use of TUEs has been under intense scrutiny in the past fortnight since the Fancy Bears computer hacking group began publishing copies of certificates issued to competitors at the Rio Olympic Games, including Froome and his former Team Sky colleague, Sir Bradley Wiggins.
Froome was issued certificates allowing him to use the drug prednisolone in May 2013 and April 2014, and says those are the only two TUEs he has benefited from in his career.
"I take my position in the sport very seriously and I know that I have to not only abide by the rules but also go above and beyond that to set a good example both morally and ethically," Froome said in a statement published on Twitter.
"It is clear that the TUE system is open to abuse and and I believe that this is something that the UCI and WADA needs to urgently address. At the same time there are athletes who not only abide by the rules that are in place, but also those of fair play.
"I have never had a 'win at all costs' approach in this regard. I am not looking to push the boundaries of the rules. I believe that this is something that athletes need to take responsibility for themselves, until more stringent protocols can be put in place."
While the information published to date by Fancy Bears does not constitute evidence of any of the athletes involved having done anything wrong - TUEs need to be justified on medical grounds to the governing bodies that issue them - the Fancy Bears leaks have heightened concerns that the system is open to abuse.
In cycling, particular attention has been paid to the three issued to Wiggins that allowed him to have an intramuscular injection of triamcinolone due to an allergy to pollen and grass seeds.
The timing of the TUEs - one each prior to the Tour de France in 2011 and 2012 and ahead of the 2013 Giro d'Italia, have caused particular concern.
Appearing on BBC1's Andrew Marr Show on Sunday, Wiggins insisted he was seeking to treat a medical condition rather than gain a competitive advantage, an assertion repeated by Team Sky boss Sir Dave Brailsford yesterday.
Today, Oleg Tinkov, the Russian entrepreneur whose Tinkoff team includes one of Froome's biggest rivals, Alberto Contador, said he believed it was impossible nowadays for an individual team to have an organsised doping programme.
Posting a picture of himself and Brailsford to Instagram, he said: "I don't understand why people are so negative and jealous, in general?
"I don't believe team Sky could ever had any organised doping programme. It is impossible in the modern cycling. Period."
Tinkov, whose team is being wound up at the end of the season following his decision to sever ties with the sport, added: "I trust Brailsford, Wiggins and Froome and I don't have to, since I probably even will never met them again."
Born in Scotland, Simon moved to London aged seven and now lives in the Oxfordshire Cotswolds with his miniature schnauzer, Elodie. He fell in love with cycling one Saturday morning in 1994 while living in Italy when Milan-San Remo went past his front door. A daily cycle commuter in London back before riding to work started to boom, he's been news editor at road.cc since 2009. Handily for work, he speaks French and Italian. He doesn't get to ride his Colnago as often as he'd like, and freely admits he's much more adept at cooking than fettling with bikes.