Paula Radcliffe has learned that her marathon world record will no longer stand after the sport's governing body changed the criteria.

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Association of Athletics Federations (IAAF), Radcliffe's 2003 mark of two hours, 15 minutes and 25 seconds is no longer valid as a world record because it was run in a mixed environment.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.

World Major Marathons (WMM) and the Association of International Marathons (AIMS) issued a joint statement calling the decision "unfair" and "confusing"