Mahmood Al Zarooni has dropped his appeal against an eight-year ban from training for doping racehorses.
The 37-year-old Emirati, who trained for Godolphin owner and Dubai ruler Sheikh Mohammed bin Rashid Al Maktoum, was last month found guilty of administering anabolic steroids to 15 horses at his stables in Newmarket, England.
"The BHA has received notice from the solicitors of Mahmood Al Zarooni that he has withdrawn his appeal regarding his eight-year disqualification," the British Horse Racing Authority said in a statement on Wednesday.
Seven further horses trained by Al Zarooni, including 2012 St Leger winner Encke, have tested positive for anabolic steroid stanozolol since he was found guilty.
Racing in Britain is going through an unprecedented period of negative publicity, with jockeys also falling foul of drugs regulations.
Italian jockey Frankie Dettori, a favourite among the British racegoing public, still hopes to ride at the flagship English Derby this Saturday despite not yet being cleared to return after a doping ban.
The French racing authority Galop banned the Italian for six months after he tested positive for cocaine at Longchamp in September, but the rider had been due to return to action last week after serving his suspension.
However, a "private matter" between Dettori and the medical committee of Galop means he is still waiting for the green light to go racing and the BHA said in a statement it would back its French counterpart's position until the situation was resolved.
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