Under new rules passed by the International Association of Athletics Federations (IAAF), Radcliffe's 2003 mark of two hours, 15 minutes and 25 seconds is no longer valid as a world record because it was run in a mixed environment.
The new rules, designed to discourage male pacemakers from helping women to achieve quicker times, means that Radcliffe's mark, set at the 2003 London Marathon is no longer a women's world record, but a world best. Her 2005 London time of 2:17:42 has been upgraded to the world record.