Tyson Fury has claimed that he has "retired" from boxing and has hit out at the sport just days after reportedly testing positive for cocaine.

The 28-year-old recently pulled out of his highly-anticipated bout with Wladimir Klitschko for unspecified reasons, which were initially put down to "medical grounds".

It was the second time that Fury had withdrawn from the fight, leaving Klitschko to turn his attention to a potential title fight with Anthony Joshua later this year.

Trainer and uncle Peter Fury announced on Sunday that the heavyweight world champion would not return to the ring this year while he 'deals with some issues', though Fury himself has now taken to Twitter to apparently announce his retirement from the sport.

In an expletive-ridden tweet, he said: "Boxing is the saddest thing I ever took part in, all a pile of shit, I'm the greatest, & I'm also retired, so go suck a dick, happy days."

Fury, who is said to have tested positive for benzoylecgonine - a compound found in cocaine - faced the prospect of losing his world title belts due to his prolonged absence from the ring.