"I was under the assumption that I wouldn't get caught."

When asked whether a clean athlete was likely to beat one using drugs in an Olympic final, Chambers added: "It's possible, but the person that's taken drugs has to be having a real bad day. That's what I believe."

Chambers returned to competition last year and was part of the victorious British 4x100m team at the European Championships in Gothenburg, while finishing fifth in the individual final.

But he has decided to switch to American football for financial reasons and is currently embarking on a career in NFL Europa with the Hamburg Sea Devils.

"We all go through different chapters in life," he said.

"I came to a crossroad in my life where I took a wrong turn, you know, got hit by a bus

"But fortunately I was able to get back up on my feet and you know, go in another direction."