Renowned National Hunt trainer Nicky Henderson faces a possible disqualification from the sport after The Queen's horse Moonlit Path failed a drugs test in February.
The Seven Barrows handler was found guilty of breaching the rules of racing in relation to the running of The Queen's Moonlit Path at Huntingdon back in February.
Moonlit Path finished sixth in the TurfTV Mares' Novices' Hurdle on February 19, after which she tested positive for tranexamic acid, an anti-bleeding drug, which contravened BHA Rule 200.
Henderson left the offices of Charles Russell Solicitors in Fleet Place, London, with no comment to make after an eight-hour hearing in front of a British Horseracing Authority disciplinary panel.
Henderson had admitted to three of the four charges with which he faced, but denied any wrongdoing in relation to Rule 200, which governs administrating or attempting to administrate a positive substance.
However, the panel, chaired by Tim Charlton QC, found him in breach of the rule, which carries an entry point in the punishment guidelines of a fine of £2,500 or a one-year disqualification.
The range of penalties start at a £1,000 fine running to £12,000, while disqualification runs from one month to five years.
Henderson also admitted to, and was found in breach of Rule 53, in that the mare tested positive, and of Rules 221 B (i) and (ii) in that the substance was administered on the day of the race or before the filly ran - and that he made inadequate medical records.
THenderson told the Racing Post: "I am obviously very disappointed with yesterday's decision and we are now awaiting the panel's written reasons for their findings, after which we will be able to discuss further with our legal advisers."
No punishment was handed out to Henderson, and none will be given until Charlton has written up his reasons for the breach of the Rules.
The panel will then meet again, on a date to be decided, to hear mitigation from Henderson's legal team before issuing a punishment.
The BHA said after the inquiry that: "With the breach of Rule 200 being of such a serious nature, they (the panel) decided to deliberate longer on a suitable penalty before reconvening on a suitable date."
Moonlit Path was making her racecourse debut at Huntingdon and finished sixth, after which the Horseracing Forensic Laboratory discovered the banned substance.
The finding was then confirmed by Laboratoire des Courses Hippiques, who performed the counter analysis.
Moonlit Path has since run three times since her sixth-placed finish at Huntingdon.

Latest Sky Sports News Report
India v Australia - Ponting
India v Australia - MS Dhoni
Mickelson enjoys China experience
HSBC Shanghai Masters - Day Four
Tottenham v Sunderland - 2nd Half
Tottenham v Sunderland - 1st Half
Man City v Burnley - 2nd Half
Ed Chamberlin expects another Arsenal victory this weekend, but Chelsea and Man United could struggle...
Alex Quinn tips up the weekend's big meetings and wonders if Sea The Stars will go to the States.
Alex Quinn asks the question everybody wants answered, can anybody stop Sea the Stars?