British heavyweight boxer Lawrence Okolie has tested positive for a banned substance ahead of his scheduled bout against French fighter Tony Yoka in Paris on 25 April, his promoter Queensberry Promotions announced on Tuesday. The failed pre-fight doping test means Okolie cannot compete, and a planned press conference in Paris was cancelled at the last minute. Promoters are now exploring the possibility of finding a replacement opponent for Yoka, who was set to headline an event at the Adidas Arena alongside compatriot Bakary Samaké.