Classic-winning Godolphin trainer Mahmood Al Zarooni is to face a British Horseracing Authority disciplinary panel hearing after samples taken from 11 horses in his care in Newmarket were found to contain traces of anabolic steroids.
Al Zarooni, who won the Ladbrokes St Leger at Doncaster last year with Encke, as well as the richest race in the world, the Dubai World Cup, with Monterosso, has trained a whole host of big-race winners since joining Sheikh Mohammed's operation and told the Godolphin website he had made a "catastrophic error".
He said on www.godolphin.com: "I deeply regret what has happened. I have made a catastrophic error.
A statement on the Godolphin website read: "Following an inspection of Zarooni's stable by officials from the BHA, traces of prohibited substances were discovered in a number of the horses tested, including Certify. The BHA has advised that, as a result, the filly will not be allowed to take part in the Qipco 1000 Guineas at Newmarket next month.
"Al Zarooni has admitted that he was responsible for the administration of the prohibited substances."
Godolphin racing manager Simon Crisford said: "This is a dark day for Godolphin. We are all shocked by what has happened.
"His Highness Sheikh Mohammed was absolutely appalled when he was told and this is completely unacceptable to him. 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 under way and we will take advice from the BHA in completing it."
Godolphin said no further comment would be made pending the completion of the BHA investigation and inquiry.
The BHA said that on April 9 this year samples were obtained from 45 horses trained by Al Zarooni at Moulton Paddocks Stables and that on Monday afternoon it had received written advice from the Horseracing Forensic Laboratory that upon analysis 11 of the samples had present in them prohibited substances, namely ethylestranol and stanozolol.
Certify, unbeaten in four career outings and winner of the Shadwell Stud Fillies' Mile at Newmarket in September, was one of the seven horses whose sample tested positive for ethylestranol. She had been ante-post favourite through the winter months for the Guineas, and only recently lost that position to the Sir Henry Cecil-trained Hot Snap.
Gold Cup runner-up Opinion Poll was one of four horses testing positive for stanozolol.
Adam Brickell, Director of Integrity, Legal and Risk for the BHA, 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 inquiry 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."
Al Zarooni enjoyed a famous night in March last year when Monterosso struck gold at Meydan, and in 2011 he won the Prince of Wales's Stakes at Royal Ascot with Rewilding.
A date for the hearing has yet to be announced.