Olympic skeleton champion Lizzy Yarnold has threatened to boycott February's World Championships in Sochi due to ongoing concerns over state-sponsored doping.
Yarnold criticised the International Bobsleigh and Skeleton Federation (IBSF) for not doing more to address concerns over the awarding of the event to the Russian city, and said she will head into the new World Cup circuit unconvinced that her sport is clean.
Yarnold is preparing to embark on a new World Cup season later this month after taking a one-year sabbatical in the wake of her Olympic triumph in Sochi in 2014.
Russia's sliding programme was implicated in a report into doping improprieties by Canadian lawyer Richard McLaren earlier this year, and a second report scheduled for December is expected to reveal further breaches.
Yarnold said: "I hope the IBSF are going to have serious discussions about what they're going to do about the World Championships in Sochi.
"We know that it may be a state-sponsored doping issue and I don't want to compete at an event where there are not clean athletes and questions over what is going to happen to my doping samples.
"We need to find out more but if nothing changes ahead of the Sochi World Championships then I wouldn't rule out not competing."
The IBSF awarded the World Championships to Sochi in June 2013, a decision which pre-dated the International Olympic Committee's announcement last year that preparations for the staging of future international winter sports events in Russia should be postponed pending the outcome of the McLaren investigation.
The IBSF, which was not immediately available for comment, has so far shown no inclination to pursue an alternative venue and Yarnold added: "I am really surprised that the IBSF haven't taken a stronger stance.
"The IOC and WADA [the world anti-doping agency] have recommended the Championships aren't in Russia and that is something I would stand by and support.
"I don't think we can be completely certain [that all athletes are clean]. There are certain nations which are not WADA-compliant, so it is a fear.
"The saddest thing is that clean athletes have been missing out on medals and titles and that really upsets me -- we will just have to wait and see what happens."
GB Bobsleigh performance director Gary Anderson echoed Yarnold's concerns, saying his team will fully review any new revelations from McLaren before deciding on a course of action.
The GB Bobsleigh team have particular reason to maintain an interest given their fifth place finish in the four-man event at the Sochi Olympics -- behind two Russian crews.
Anderson said: "We've got to make a big decision with regard to attending the Worlds. We have to think about the athletes, the programme and Great Britain.
"All that has to be taken into account when we make the decision because at the moment it [competing in Russia] is not something I look forward to."