On July 17, 2014, the British Horse Racing Authority announced that five horses had tested positive for the banned substance morphine at recent meets. One of the horses is owned by the Queen. Estimate, a five-year-old filly, tested positive after placing second in the Gold Cup at Royal Ascot, a race she won in 2013.

It is believed Estimate consumed contaminated feed. If this is not proven to be the case, however, the filly could be disqualified from the race and forfeit the £80,625 prize money.

A statement by John Warren, the Queen’s Bloodstock and Racing Advisor, said: “On Thursday July 17 the British Horseracing Authority (BHA) announced that a number of post-race samples, obtained from recent race meetings, had been found to indicate the presence of morphine, which is a prohibited substance on race days. Five horses, under the care of various trainers, were affected.

“I can confirm that one of those horses was Estimate, the five year-old filly trained by Sir Michael Stoute and owned by The Queen.

“Initial indications are that the positive test resulted from the consumption of a contaminated feed product.

“Sir Michael is working closely with the feed company involved to discover how the product may have become contaminated prior to delivery to his stables.

“As the BHA investigates this matter, including potential links between the different cases, Sir Michael continues to offer his full co-operation.

“There will be no further comment until the BHA announces its considered findings. Her Majesty has been informed of the situation.”

The BHA said in an earlier statement: “Once all processes have been completed the cases will be put before a disciplinary panel who will decide what action, if any, should be taken. This may include the disqualification of the horses in question from the relevant races.”

Following the news, animal feed manufacturer Dodson & Horrell announced that they are holding a full investigation into how possible component contamination could have occurred.

Dodson & Horrell, horse and dog food manufacturer to the Queen since 2006, identified Alfalfa Oil Plus as the possible product which had been contaminated. The company said it has launched a “thorough investigation” with its unnamed supplier of a component.

Dodson & Horrell believes contamination could have occurred from poppy seeds that occur naturally in the environment.

A statement issued on behalf of Dodson & Horrell said: “Preliminary investigations suggest that any contamination of this component product did not occur at Dodson & Horrell’s site. The investigation is currently centring on Dodson & Horrell’s supplier.

“Dodson & Horrell has recalled batch numbers week 20-28 of Alfalfa Oil Plus as a precautionary measure, in accordance with our procedures and NOPS (naturally occurring prohibited substances) protocol.

“No positive test results have been recorded in any other Dodson & Horrell product currently in the market.

“From information currently available to us, it appears that any contamination may have come from poppy seeds that occur naturally in the environment. Please note this does not affect the welfare of the animal.

“Investigations are ongoing through the official and correct channels. Information will be shared by Dodson & Horrell as it becomes available.”

Estimate, trained in Newmarket by Sir Michael Stoute, produced one of the headline stories of last season with a nail-biting triumph in the Gold Cup at the Royal meeting. She then went down narrowly to Leading Light in the defence of her crown last month.

She is reportedly still in contention for the Artemis Goodwood Cup next Thursday and worked on Wednesday morning over nine furlongs in Newmarket alongside stablemates Snow Sky and Top Tug.