Banned trainer Mahmood Al Zarooni worked alone, according to a British Horseracing Authority (BHA) investigation that ended last week. No further disciplinary charges are to be issued.

Al Zarooni was banned for 8 years on 25 April after 22 horses tested positive for anabolic steroids (news, 2 May).

The BHA said the investigation confirmed “Al Zarooni was the person solely responsible for the events that took place”.

But it has highlighted a “number of key failings” in the management structure at the yard, in which “these offences were able to be perpetrated by Al Zarooni without being detected by others”.

Former assistant trainer Charlie Appleby is now in charge of the 200 horses at the Newmarket yard owned by Godolphin.

This news story was first published in Horse & Hound magazine (1 August 2013)