Fresh doubts have been cast on the legitimacy of the women’s 400m world record after allegations from one of Germany’s leading anti-doping experts that Marita Koch was part of the state-sponsored doping programme in East Germany.

Koch, who was Olympic 400m champion in 1980, set the current world record of 47.60 in 1985, and was also the first woman to run under 22 seconds for 200m, running 21.71 in 1979.

However a report today by the Ed Harris of the BBC’s World Service suggests that her performances were not achieved by legal means. “Koch competed in an era when we know East Germany was systematically doping its athletes,” said Harris. “If so many were [doping], why should we believe she was clean?”

Koch spoke to Harris about the allegations at the IAAF Gala in Monaco last year, where the former athlete was inducted into the Hall of Fame along with fellow East German athlete Heike Drechsler. “I don’t have to prove anything,” said Koch. “I have a clear conscience. I can only repeat myself: I never tested positive, I never did anything I shouldn’t have done at the time. I know what I trained for those 12, 15 years. I slowly improved my time. All world records are in some way an exception, so now the next person has to come and break that record. At some point that time will come.”

Werner Franke, one of the world’s most respected biochemical researchers, was one of the first to shed light on the practices in East Germany. He and his wife, Brigitte Berendonk, gained access to official medical records and research of the nation’s Olympic athletes, and later made public the full extent of the doping practices. He is unwilling to yield on his stance that Koch’s performances were fuelled by steroids, and says he would welcome the chance to prove his case if she took him to court.

“There was a newspaper [report] where she announced she would go against my wife, and I said please do,” said Franke. “That would be the best way of bringing out the truth, [to bring] all the materials, all the volumes of reports of her doctor to court.”

Speaking to the BBC World Service today, Harris explained why the IAAF has not acted on Franke’s revelations. “That data detailing the dosages of these athletes has been used on numerous occasions in German courts over the past 25 years to seek compensation for German athletes suffering health problems as a result of taking these substances,” he said. “The IAAF has never used these figures to launch its own investigation. The IAAF told me ‘there’s a 10-year statute of limitations in the WADA code to which the IAAF is in full compliance, though should the athlete admit to having used or taken advantage of substances of techniques prohibited at the time, the IAAF can subsequently remove an athlete’s performance from the record books.”

Koch, though, appears to show no sign of admitting any wrongdoing. “Everyone who knows me knows that I don’t seek the publicity,” she said. “If I’m asked, then I answer, other than that, I just have to live with it.”

To watch Harris, Franke and Koch speak about the allegations, check out the discussion on the BBC World Service page here.