Billionaire businessman and racehorse trainer Luke Comer has been declared a disqualified person from horse racing by the Irish Horseracing Regulatory Board (IHRB) after failing to pay arrears exceeding €1.3 million in penalties and costs.

Comer was placed on the regulator's latest forfeit list after failing to discharge the financial penalties imposed on him. The arrears stem from a high-profile equine anti-doping investigation following an IHRB inspection at his stables near Kilternan, County Dublin, in late 2021, where 12 horses tested positive for the anabolic steroids methandienone and methyltestosterone.

The regulatory case resulted in Comer losing his licence to train horses for three years, along with fines exceeding €85,000 and an order to pay €775,000 in legal costs to the regulatory body. An IHRB referrals committee found no evidence of deliberate doping and could not determine how the steroids entered the horses' systems, but held Comer responsible as the licence holder.

Comer, who resides primarily in Monaco, has consistently denied any wrongdoing or knowledge of how the prohibited substances were administered. Appeals by both Comer and the regulator against the initial penalties were dismissed in 2024. Earlier this year, the IHRB initiated High Court proceedings in relation to the outstanding fine and costs.