No sooner had the IAAF unveiled Maurice Greene as one of its worldwide ambassadors than the Olympic 100 metres champion and former world record holder was alleged by a witness in a forthcoming trial to have paid for performance-enhancing drugs.

	'Embarrassing situation': Maurice Greene has denied the allegations

You can imagine the sense of frustration at IAAF headquarters in Monaco.

Having done their best to erase all trace of Marion Jones from the record books following her admission of drug taking and subsequent jailing, only weeks later the sport's world governing body have had to field questions from around the world on what lies at the heart of the Greene allegations.

It is claimed that Greene, 33, who retired at the start of the year, has been named among 12 athletes - who between them have won 26 Olympic and 21 World Championship medals - who were supplied with performance-enhancing drugs by Angel Guillermo Heredia, a former discus thrower from Mexico.