Top National Hunt trainer Nicky Henderson has been found guilty of administering a prohibited substance to one of his horses and faces a possible ban from the sport.

Mr Henderson was found guilty of breaching four racing rules at a British Horseracing Authority (BHA) hearing yesterday (Monday 22 June).

Moonlit Path, who Mr Henderson trains for The Queen, failed a drugs test after her debut race at Huntingdon in February. Moonlit Path finished sixth in the mares’ novice hurdle.

But the horse subsequently tested positive for the banned substance tranexamic acid, under the brand name Cyklokapron — which is used to prevent haemorrhaging.

Although it can be used legally in training, it must not be in the horse’s system on a raceday.

Mr Henderson admitted breaching rules regarding the mare being administered with the substance, admitting that it was administered on the day of racing without seeking dispensation from a veterinary officer and that he failed to keep suitable records of the treatment.

But he denied breaching rule 200, which governs administrating or attempting to administrate a prohibited substance either with the intention of affecting her racing performance or in the knowledge that her racing performance could be affected by such a substance.

The disciplinary panel will now consider a suitable penalty.

The offence is punishable with a fine of between £1,000 and £12,000 or a ban from the sport ranging from one month to five years.

No timescales have been given on when a decision will be reached.