Roberts, from Fresno in California, provided an in-competition sample on May 19, following the British Basketball League Play-offs Final between his former team London City Royals and Leicester Riders.

Analysis of his sample returned an Adverse Analytical Finding for carboxy-THC, a metabolite of cannabis. 

Carboxy-THC is prohibited under section S8 of the World Anti-Doping Agency (WADA) 2019 Prohibited List. 

It is a specified substance and is prohibited in-competition only.

Roberts was charged with violating Anti-Doping Rule Article 2.1 – "Presence of a Prohibited Substance or its Metabolites or Markers". 

The 29-year-old accepted the presence of carboxy-THC in his A-sample, stating that he ingested it out-of-competition between May 13 and 17.

He says the cannabis was in a chocolate brownie given to him by a friend.

Kim Wolff, the head of the Drug Control Centre at King’s College London, having considered Roberts' account, accepted that it was entirely possible that his ingestion of cannabis took place out-of-competition. 

Accordingly, the period of ineligibility is two years.

"While some recreational drugs may not particularly enhance sporting performance, there are still significant and valid reasons why they are named on WADA’s Prohibited List," Pat Myhill, UKAD’s director of operations, said. 

"Cannabis is banned in-competition and athletes are solely responsible for what is in their system, regardless of whether there is an intention to cheat or not. 

"Sportspeople must be aware that using cannabis, even out-of-competition, will put them at risk of breaking the anti-doping rules and receiving a ban."

The period of ineligibility commenced on May 19, 2019 and will expire on May 18, 2021 inclusive.