This was reported by The Standard newspaper in Kenya and the athlete in question has now been named by the Daily Mail as Beijing 2008 Olympic 1500 metres champion Asbel Kiprop.

The Standard did not identify the name or gender of the athlete, but cite "impeccable sources" in reporting they tested positive for banned blood booster erythropoietin (EPO) during out-of-competition testing.

The Daily Mail cited "senior athletics sources" in reporting that it was Kiprop, a three-time world 1500m champion and the third fastest man in history.

The 28-year-old rose to prominence as a teenager when finishing second in the Olympic 1500m final at Beijing 2008 behind Bahrain's Rashid Ramzi.

He was upgraded to gold after Ramzi tested positive for continuous erythropoietin receptor activator (CERA).

Kiprop then successive World Championships titles at Daegu 2011, Moscow 2013 and Beijing 2015.

In 2015 he also clocked a personal best of 3min 26.69sec at the International Association of Athletics Federations (IAAF) Diamond League in Monaco to make him the third fastest man in history.

He finished a disappointing sixth at Rio 2016 and ninth at last year's IAAF World Championships in London.

EPO is the same substance which two high-profile female Kenyan marathon runners have tested positive for in recent years