The scandal over allegations of blood doping in athletics has spread to the London marathon, with claims that it has been won seven times in 12 years by runners with suspicious blood scores.

The latest findings in the Sunday Times based on a major leak of drug data tests is claimed to cast a shadow over almost a third of winners in 24 London men’s and women’s races between 2001 and 2012, and in other world city marathons.

The organisers of the London and Chicago marathons have told the paper the International Association of Athletics Federations, and the national anti-doping authorities failed to tell them that some athletes were competing with blood that appeared so heavily doped as to threaten their health.

The marathons worst affected were Chicago, London, New York and Boston. In London, seven first places, six second and seven thirds were taken by athletes with blood tests deemed suspicious by experts who analysed the leaked database. However not all the tests were taken at the time of the marathons – some date to other points in the athletes’ careers.

In a statement, London marathon chief executive Nick Bitel said the race organisers were “very concerned” about the allegations, and in a radio interview he added more direct criticism of the IAAF, saying: “What this story is really about is the IAAF’s failure to take effective action.

“We are disappointed. We’re doing more than anybody else to fight doping in our sport. We were the first people to call for blood testing and in fact we’re still probably the only event in the world that blood tests all our athletes,” he said in a Radio Five Live Sportsweek interview.

He insisted that, although the organisers were paying “thousands of pounds” for athlete testing, they were not told of the results by the IAAF, and had been unaware of the suspicious data.

“The IAAF needs to do more to stop people from starting who have blood values that are out of normal range.”



In an earlier statement, he said: “We believe there are people in our sport who are cheating and everyone has a part to play to protect those who are not. We continue to be at the forefront of anti-doping measures for marathon runners as we are determined to make marathon running a safe haven from doping but we cannot do it all on our own and rely heavily on the IAAF.”



“We are therefore very concerned by the allegations made in the Sunday Times today and we will be discussing the implications of the allegations with the IAAF.”

Athletes with suspicious blood scores are said to have collected more than £3m in prize money for winning city marathons.

The experts concluded that some of the athletes ran the risk of a stroke or heart attack by using blood transfusions or banned red-cell-boosting drugs, which had the effect of making their blood so dense that they should have been seeking hospital treatment rather than competing.

The leaked database contains more than 12,000 blood tests, from 5,000 athletes including many household names. The test scores – which can suggest, but not prove, illegal doping – were analysed by Michael Ashenden and Robin Parisotto, experts on doping, who concluded that a third of all medals in the Olympics and world championships endurance events were won by athletes with suspicious blood results.

Some of the most extreme results related to the Russian Liliya Shobukhova, three times winner of the Chicago marathon who also took the title in London in 2010 and came second in 2011, who is said to have recorded extremely high blood scores over nine years, before the athletics authorities took action. On Thursday the IAAF announced that all her results since 2009 had been annulled, and the two-year ban imposed last year extended by 14 months.

The London Marathon organisers have threatened to take legal action to recover prize money she won.

On Friday the World Anti-Doping Agency (Wada) announced an urgent investigation into the claims, which have led athletes including British Olympic gold medalist Mo Farah to promise to publish their own blood test data to prove that they are clean. The IAAF has agreed to hand over its full database to Wada, but has also written to the Sunday Times demanding that it destroys its copy.