The 26-year-old Scot, who won the Great Scottish Run in 2011, said in a statement on Twitter that he had made "an incredibly stupid and uncharacteristic mistake".

Traynor stressed that the drug had been taken socially and not in order to enhance performance.

"This was devastating news for me and I take full responsibility," he said, as he revealed he had tested positive "for benzoylecgonine, a metabolite of cocaine".

Traynor added: "I am sorry to my family, friends, coaches, sponsors and anybody who has supported my progress at any stage of my career.

"I want to make it completely clear that my violation was in no relation to sport or enhancing performance.

"This happened as a one-off and in a purely social situation with a drug I should never have taken."

Traynor, who runs for Giffnock North and Tulsa University, competed for Britain at the World Cross-Country Championships in Aarhus in March, finishing 109th, and was 38th at the World Half Marathon Championships last year.

He said he had accepted his " mistake" and needed to come to terms with "the final punishment", adding: "I have cooperated fully with all relevant bodies and will now face the severe consequences, the extent to which is still not certain but could be up to a four-year ban.

"I live a sporting lifestyle to compete.

"Athletics is my passion.

"It's all I think about, it's what gets me out of bed in the morning.

"I am yet to come to terms with the fact that I have ruined this for myself with one senseless act.

"I only ask that people understand that this was a stupid mistake, had nothing to do with trying to enhance performance and, in fact, had the opposite effect."