A second English trainer has admitted to using banned anabolic steroids on horses in his care.

Gerard Butler's admission comes just days after his Newmarket neighbour, Godolphin trainer Mahmood Al Zarooni, was banned for eight years for injecting horses with anabolic steroids.

Butler told the Independent he had made an "unpardonable misjudgment".

The trainer said he had already informed the British Horseracing Authority several of his horses had been treated, on veterinary advice, for injured joints with a banned substance.

"I have been totally candid throughout, and it was I who told the BHA that I had treated four colts in December and January," Butler told the Independent.

"I'm not trying to defend myself, just to explain what happened. And I must emphasise I was advised in good faith by my vets.

"It was an unpardonable misjudgment, purely to cut corners in what is a very expensive treatment.

"I have been very uncomfortable over the past few days, hearing and reading about the Al Zarooni case.

"I feel people need to know about what has happened in my yard."

Butler believes "Sungate", the medication in question he used on veterinary advice to treat horses' joints, has been "misunderstood by many others".

"I know I'm obliged to satisfy myself that each and every treatment is within the rules, and I failed to do so in this case," he said.

"But I am certain that this medication has been misunderstood by many others.

"And I just hope that the BHA is being suitably rigorous in establishing whether that is indeed the case.

"It did not cross my mind that there could be any problem with this medication.

"And, judging from the fact that the BHA said nothing about it when they saw my medical book, it does not seem to have crossed their minds, either.

"Little Black Book ran on August 4, and won a couple of weeks later, so they would have known he was clearly in training at the time.

"In the medical book, I signed that I had authorised use of the drug, and my vet had countersigned for its administration."