Racehorse trainer Mahmood Al Zarooni has been disqualified for eight years after 11 of his horses tested positive for anabolic steroids.
The 37-year-old was given the punishment after a disciplinary hearing at the British Horeseracing Authority in London.
The BHA made the announcement on social media, tweeting: "Mahmood Al Zarooni has been disqualified for eight years following today's Disciplinary Panel hearing."
The scandal has already caused Al Zarooni's stables to be locked down by renowned owner Sheikh Mohammed, saying he was "appalled and angered" by events.
Al Zarooni was charged with rule breaches related to prohibited substances, duty to keep medication records, and conduct prejudicial to racing.
He admitted wrongdoing ahead of today's hearing, in which he was not being legally represented, saying he had made a "catastrophic error".
Speaking on Monday, he said he did not realise he had broken any rules as the horses were not racing at the time.
Samples were taken earlier this month from 45 horses trained by Al Zarooni at Moulton Paddocks Stables, Newmarket.
Subsequent analysis showed 11 of the samples contained ethylestranol and stanozolol, which are prohibited substances.