Godolphin trainer Mahmood Al Zarooni has appealed against an eight-year ban for doping horses with anabolic steroids, the British Horseracing Authority (BHA) has said.
Al Zarooni was banned last month after 11 horses in his care at his Newmarket stables tested positive and he admitted administering prohibited substances to four others.
The BHA accused the employee of Dubai ruler and Godolphin owner Sheikh Mohammed bin Rashid al-Maktoum of a "deliberate flouting" of the rules and "widespread systematic misuse of illegal substances".
The BHA said in a statement Al Zarooni will now contest the length of the eight-year ban, with the date for the appeal hearing to be confirmed in due course.
He will be represented by William Clegg QC, instructed by Russell-Cooke Solicitors, London.
The Dubai-born handler admitted all the breaches of the rules and apologised for his actions at his disciplinary hearing, at which he waived the right of legal representation.
Al Zarooni was, according to the BHA's official findings, guilty of a "widespread systematic misuse of illegal substances".
The BHA said all the horses which were under the care of Al Zarooni have now been tested, with the results to be confirmed in due course.