Tyson Fury must enrol in the WBC clean boxing programme this week if he wants to fight for Deontay Wilder's world title, says WBC president Mauricio Sulaiman.
WBC champion Wilder has announced he will make his next title defence against Fury in Los Angeles on December 1, but the governing body are yet to sanction the heavyweight showdown.
Sulaiman is hopeful the 'Gypsy King' will sign up and accept out of competition drug testing but made it clear he needs to do it in the next seven days, or he will not win the WBC title, even if he beats Wilder.
"If he does not enrol, then the WBC cannot sanction the fight," Sulaiman exclusively told Sky Sports.
"If Tyson Fury does not enrol in the clean boxing programme, the fight is not for the WBC title. He cannot win the title.
"He told me personally, publicly on Twitter. He sent a message, he had a fight, and he has been struggling with paperwork, so we understand that. We have that flexibility in our protocol, but now it's time. Time is now."
Asked when Fury must enrol, Sulaiman added: "I would say this week. I'm going to reach out to him, because there has to be testing for the fight, out of competition. The time is of essence.
"Hopefully he will enrol."
The WBC and VADA (Voluntary Anti-Doping Assocation) joined forces in 2016 to eradicate drugs in boxing.
The voluntary enrolment means fighters can be tested outside the competition timescale and boxers can also take part in an awareness programme "to educate and prevent boxers about the dangers of substances and the tragic effects that they can lead to".
Tyson Fury's management team have declined to comment.
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