World heavyweight champion Tyson Fury says he has retired from boxing in an expletive-laden message on Twitter.

The Briton, 28, withdrew from a rematch with Ukrainian Wladimir Klitschko, scheduled for 29 October, because of reported mental health issues.

Tyson Fury

Fury, who holds the WBA and WBO titles,faces a hearing into a charge for an alleged doping violation in November.

“Boxing is the saddest thing I ever took part in” read his tweet, adding: “I’m the greatest, and also retired.”

Fury had been scheduled to earn the biggest purse of his career for his second fight with Klitschko at the Manchester Arena this month.

He postponed the original rematch against the Ukrainian, which was scheduled for July, after injuring an ankle in training.

He has been given 10 days by the World Boxing Organisation to provide detailed reasons for his second withdrawal.

Fury is under investigation, having been charged by the UK Anti-Doping Agency (Ukad) in June, after traces of a banned substance were allegedly found in a urine sample.

The fighter has denied allegations of doping.

It has also been alleged he refused to give a sample having been visited by Ukad. An athlete who refuses to take a drugs test can be banned for four years.

In November, Fury beat Klitschko on points in Germany – the 40-year-old’s first loss since 2004 – to gain the WBA, IBF, WBO and IBO titles, with American Deontay Wilder holding the WBC belt.

Within two weeks Fury was stripped of the IBF title because he was unable to fight mandatory challenger Vyacheslav Glazkov – and that belt is now held by rival British world heavyweight champion Anthony Joshua.