Godolphin trainer Al Zarooni has been charged with doping horses and will appear before a BHA disciplinary panel on today. Earlier in the week the trainer admitted to making “a catastrophic mistake”.

Al Zarooni faces several counts related to prohibited substances, medical records and conduct prejudicial to horse racing.

Al Zarooni could lose his training licence and news from the British Horseracing Authority states he has admitted giving anabolic steroids to four other horses; Comitas, Sashiko, Vacationer and Tearless on top of the 11 tested. However further charges cannot be brought as these animals were not tested.

Of the 45 horses trained by Al Zarooni and tested by the BHA 11 horses had samples found to contain prohibited substances ethylestrenol and stanozolol, who, with wins combined have earned more than £1.31m in prize money, include unbeaten Certify. They have been suspended from racing for an indefinite period.

“The use of anabolic steroids is prohibited at all times for any horse registered as ‘in training’ under the care of a trainer licensed by the BHA,” it said.

In 2012, of the 90,174 runners on race days, 7,182 samples were taken. Some 14 positive tests were found, a figure down from 25 in 2010.

Around 700 tests were carried out during training in 2012, although the BHA did not disclose any details about the number of positive tests.

Simon Crisford, the racing manger for Godolphin, said in a statement on Monday that they were to urgently review all procedures and controls.