Doping results a shock to us, says London Marathon boss
London Marathon chief executive Nick Bitel has criticised world governing body the IAAF and said race organisers are "very concerned" by claims that seven winners in a 12-year period recorded suspicious blood scores.
The Sunday Times has published fresh allegations after its analysis of drugs test data from 2001 to 2012.
It said the winners of 34 major marathons around the world - one in four - during the period should have faced censure or investigation because of their test results, with those athletes collecting more than £3m in prize money. The paper also published anti-doping blood test data from athletes including double Olympic champion Mo Farah, who said he will do what it takes to prove he is a clean athlete.
He is one of eight British competitors defying athletics authorities by agreeing for blood test data - which show results fall within the normal expected range - to be made public by the newspaper.
London was the worst affected of the marathons, with seven wins, six second places and seven third places out of 24 men's and women's races allegedly involving suspicious blood scores.
Mr Bitel criticised the IAAF, saying that although the Marathon pays for its own drugs testing, it does not administer the programme and does not get to see the results, meaning organisers had been unaware of the suspicious blood data.
"We are disappointed," he said. "We're doing more than anybody else to fight doping in our sport."