Mahmood Al Zarooni, one of two licensed trainers for Sheikh Mohammed’s Godolphin operation, is to face a BHA disciplinary hearing after 11 horses in his care tested positive for prohibited substances.

The unbeaten Group 1 winner Certify, who was being offered at odds of 7/1 in the betting for the 1,000 Guineas, was among those to return a positive test, along with multiple Group-winning stayer Opinion Poll.

Ethylestranol, an anabolic steroid, was the banned substance found in samples taken from Certify, Desert Blossom, Fair Hill, Ghostflower, Orkney Island, Sweet Rose and Valley Of Queens, while a different anabolic steroid, Stanozolol, was found in samples from Artigiano, Bathrat Amal, Opinion Poll and Restraint Of Trade. The tests were carried out under the ‘testing in training’ programme on April 9, 2013. In total, 45 horses were tested at Godolphin’s Moulton Paddocks Stables on the edge of Newmarket.

Adam Brickell, Director of Integrity, Legal and Risk for the BHA, said: said: “Ethylestranol and stanozolol are anabolic steroids and therefore prohibited substances under British Rules of Racing, at any time – either in training or racing.

“Mahmood Al Zarooni has been advised of the analysts’ findings and has been visited by an investigating officer.

“A Disciplinary Panel enquiry into the analysts’ findings will take place at the first available opportunity, confirmed details of which will follow when available. The horses which have produced positive tests will also not be permitted to race with immediate effect and for an extended period of time.

“As part of the ongoing process a decision will be made as to what period this suspension will be imposed for. 

The BHA understand the importance of this process being carried out as quickly as possible because of implications for betting markets.”

In a statement issued by Godolphin, Sheikh Mohammed was said to be “absolutely appalled” at the findings.

Simon Crisford, Racing Manager for Godolphin, said: “This is a dark day for Godolphin. We are all shocked by what has happened. We will await the outcome of the BHA inquiry before taking any further internal action.

“Sheikh Mohammed has instructed me to begin an urgent review of all of our procedures and controls. That is already underway and we will take advice from the BHA in completing it.”

Admitting responsibility for administering the banned substances, Al Zarooni said: “I deeply regret what has happened. I have made a catastrophic error. Because the horses involved were not racing at the time, I did not realise that what I was doing was in breach of the rules of racing. I can only apologise for the damage this will cause to Godolphin and to racing generally.”