UK Anti-Doping chief: We are 'confident about testing regime'

The organisers of the London Marathon have accused athletics' world governing body of failing to take effective action against doping.

It follows new allegations published by The Sunday Times, which claims the race has been won seven times in recent years by athletes with questionable blood test results.

London Marathon's chief executive says he is is 'very concerned' and has called on the International Association of Athletics Federations to do more to combat cheating.

UK Anti-Doping chief Nicole Sapstead says she has confidence in UKAD's testing regime and in the investigation into the allegations.