Mahmood Al Zarooni has confessed that he brought anabolic steroids that were found in 15 horses at the Godolphin stable to the Newmarket yard into the country.

The trainer, who was banned for eight years by the British Horseracing Authority last week, collected the drugs during a trip to Dubai, before driving to the stable and passing them to an assistant vet to administer.

The revelation was made in a full report by the BHA, which read: "[Al-Zarooni] then drove to Moulton Paddocks Stables and passed the syringes out of his car window to an unqualified veterinary assistant, Sharif Mahboob, and asked him to give the drugs to [the] horses which he listed on a piece of paper."

It then went on to accuse Al Zarooni of having "damaged the reputation of British racing" as a result of his conduct: "The conduct of high profile trainers is keenly watched by all stakeholders in the sport. Al-Zarooni administered anabolic steroids to a significant number of horses in training

"This is a very serious departure from the proper governance standards expected in horse racing. The panel consider that Al-Zarooni's actions have damaged the reputation of British racing. The gravity of Al-Zarooni's breach means that the appropriate penalty must be at the upper end of the range."

The 15 horses involved in the case have been suspended for six months.