British Olympic sprinter Nigel Levine has been banned from all sport for four years after failing a drugs test.
The European 4x400m relay gold medallist was provisionally suspended in December.
And UK Anti-Doping has now confirmed the 29-year-old tested positive for banned asthma drug clenbuterol following an out-of-competition test on 24 November 2017.
Levine was part of Britain's 4x400m relay team at the 2016 Rio Olympics.
Clenbuterol is on the World Anti-Doping Agency's prohibited list because it is deemed a performance-enhancing drug and can induce weight loss.
Levine, an indoor and outdoor European 4x400m relay champion, has not raced since he broke his pelvis in a motorbike crash in Spain in January 2017, an accident which also involved compatriot James Ellington.
Ukad chief executive Nicole Sapstead said: "All athletes must adhere to the principle of strict liability, and are solely responsible for any substances found in their system.
"Mr Levine is an elite athlete, who has competed at the Olympic Games, European and World Championships, and has received significant anti-doping education throughout his career.
"It is up to role models such as Mr Levine to uphold the highest standards when it comes to anti-doping, ensuring they check all supplements thoroughly and are 100% certain they know that what they are consuming is not prohibited."