Athletics chief Lord Coe has declared that he "won't fail" to clean up the sport following revelations of "state-sponsored" Russian doping.
A damning report said the London 2012 Olympic Games was "sabotaged" by the presence of Russian athletes with suspicious doping profiles.
An independent commission set up by the World Anti-Doping Agency (WADA) revealed 1,417 samples were deliberately destroyed on the orders of the director of Russia's drug-testing laboratory.
Lord Coe, president of the athletics governing body the IAAF, was questioned about cleaning up athletics at a Microsoft event in London hosted by Clare Balding.
He said: "I won't fail, but I also accept that this is a huge journey."
He added: "This isn't six weeks to fix things. This is a long journey and we have to start somewhere, and I know what I have to do.
"It's actually just nice to be here for some distraction."