London, August 9

Seven London Marathon winners in 12 years have recorded blood level results which suggested they may have been doping, the Sunday Times newspaper reported in the latest set of allegations to have rocked athletics.

It reported that 32 winners of major city marathons — London, Boston, Chicago, New York, Berlin and Tokyo — should have faced investigation over potential blood doping following test results — a quarter of the overall total. The newspaper did not provide dates for when its statistics allegedly apply or identify athletes involved.

London Marathon chief executive Nick Bitel said in a statement on Sunday that organisers were “very concerned” by the allegations and said the race had a “zero tolerance policy” on doping. In a separate development Britain’s Mo Farah — who won Olympic gold medals in 2012 for the 5,000m and 10,000m — is one of eight athletes who have agreed to release their own blood test data, the paper reported. His coach Alberto Salazar has faced doping allegations but both he and Farah deny any wrongdoing.