Walker, who plays for rugby league side Wakefield Trinity, tested positive for benzoylecgonine - a metabolite of cocaine - after a match against Widnes Vikings in July of last year.

He becomes the 35th rugby league or union player to be punished by UKAD for a breach of anti-doping rules.

Over half of the total of 68 sanctions currently listed by UKAD are rugby players.

Walker's suspension has been backdated to the date of the failed test and he will be free to resume his career in March.

He has been banned by the Rugby Football League, the sport's governing body in the country, since July 2017.

Walker claimed his ingestion of cocaine, a prohibited stimulant, was out-of-competition "in a context unrelated to sporting performance".

The 27-year-old prop said he had taken the substance three days prior to the match, which Wakefield Trinity won 36-8.

UKAD chief executive Nicole Sapstead appeared to suggest Walker, named in Scotland's provisional squad for the 2017 World Cup before he was later cut from the list, had not taken the substance in order to improve his performance.

"While UKAD accepts anti-doping rule violations don’t always stem from a deliberate intention to cheat, athletes must always adhere to the principle of strict liability," she said.

“Cocaine 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 cocaine, even out-of-competition, will put them at risk of breaking the anti-doping rules and receiving a long ban.”