London: Tyson Fury has given up his WBO and WBA world heavyweight titles "with immediate effect" to concentrate on his "medical treatment and recovery", said a statement released by his promoters Hennessy Sports.
The British boxer has admitted taking cocaine to deal with depression and was set to be stripped of his titles after cancelling two planned rematches this year against Ukrainian former champion Wladimir Klitschko.
"I feel that it is only fair and right and for the good of boxing to keep the titles active and allow the other contenders to fight for the vacant belts that I proudly won and held as the undefeated heavyweight champion of the world when I defeated the long-standing champion Wladimir Klitschko," Fury said in the statement released late yesterday.
"I won the titles in the ring and I believe that they should be lost in the ring, but I'm unable to defend at this time."
Mick Hennessy, Fury's promoter, said the decision was "heartbreaking".
Peter Fury, Tyson's uncle and trainer, said: "Tyson will be back stronger from this and I will make sure, no matter what we have to deal with, Tyson not only comes back but will reclaim what's rightfully his.
"I'm very proud of my nephew's achievements."
Fury had already withdrawn from a rematch with Klitschko on October 29 because of mental health issues. He also cancelled their first planned rematch in July citing an ankle injury.
The outspoken boxer admitted in an interview with Rolling Stone magazine this month that he was suffering from depression and taking cocaine.
The British Boxing Board of Control (BBBC) met on Wednesday to discuss whether to remove Fury's boxing licence following the admission of drug taking.
They had been due to release their decision on Thursday.
Controversial Fury, 28, announced earlier this month he was retiring only to make a U-turn just hours later following media reports he had failed a drug test for cocaine.
Fury then confirmed for the first time that he had taken the class A drug as a way of self-medicating for severe depression.