The 29-year-old Levine, who represented Britain at the 2012 and 2016 Olympic Games in London and Rio de Janeiro respectively, completed an out-of-competition test on November 24 last year which came out positive for the prohibited substance clenbuterol.

The substance can be used to treat asthma but has been also used for performance-enhancing purposes.

He claimed that the positive test was due to supplements he had been taking, but this was rejected and he was found to have contravened Article 2.1 of the Anti-Doping Rules, "Presence of a Prohibited Substance or its Metabolites or Markers in an Athlete’s Sample". 

Levine was provisionally suspended on December 13 in 2017, and his four-year ban and is due to run from there until December 12 in 2021. 

"All athletes must adhere to the principle of strict liability, and are solely responsible for any substances found in their system," Nicole Sapstead, UKAD chief executive, said. 

"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 per cent certain they know that what they are consuming is not prohibited."

Levine had been part of Great Britain's 4x400 metres relay team for over 10 years, winning eight World and European Championship medals in the process.

He also won an individual silver medal in the 400m at the 2013 European Indoor Championships.

In January 2017, Levine broke his pelvis in in a motorbike crash, an accident which also involved fellow British athlete James Ellington, and has not competed since then. 

Clenbuterol is not an anabolic steroid, but it has some properties similar to those of steroids, such as promoting an increase in muscle mass

The most high-profile case in recent years of an athlete testing positive for clenbuterol was cyclist Alberto Contador of Spain.

He was banned for two years from professional cycling after testing positive for the drug at the 2010 Tour de France.

He was later stripped of the 2010 title of the Tour de France and the 2011 title of the Giro d'Italia..

The Court of Arbitration for Sport found that Contador probably tested positive due to a contaminated food supplement.