Controversy reigned at Yarmouth when it was discovered that the Charlie McBride-trained Mandarin Princess, winner of the opening two-year-old race, was in fact stablemate Millie's Kiss.

The mistake was only discovered after the 50-1 outsider had overturned the 4-6 hot-pot Fyre Cay on her racecourse debut in the six-furlong novice auction stakes for juveniles.

Millie's Kiss, a three-year-old with plenty of racecourse experience, was due to run in the nine-furlong handicap later on the card but was subsequently withdrawn.

A report issued by the British Horseracing Authority: "The stewards held an inquiry to consider the circumstances surrounding the identification of the winner, Mandarin Princess, trained by Philip (Charlie) McBride, which was presented at the sampling unit for routine testing.

"The scan identified the horse to be Millie's Kiss, the trainer's other runner in race four.

"They interviewed the trainer, the stable groom, the veterinary officer and the equine welfare integrity officer responsible for the sampling unit.

"Having heard their evidence they referred the matter to the head office of the British Horseracing Authority and ordered Millie's Kiss to be withdrawn from race four."

Despite the wrong horse having won the race, the result is set to stand - for the time being.

Stipendiary steward Tony McGlone told At The Races: "As all horses are, they are brought into the stables and they are scanned and are allocated into their boxes.

"These two horses, trained by Charlie McBride, were given a box each.

"Mr McBride went over to the weighing room to collect the saddle and was slightly delayed collecting it. He rushed over.

"The stable girl had taken the horse out of the stables and put it in the saddling boxes. Mr McBride put the saddle on, the horse ran, it won.

"We then sent the horse for routine testing as per normal.

"The integrity officer scanned the horse and found it to be the wrong horse.

"We have referred it to the British Horseracing Authority for further consideration.

"I think the BHA have got 14 days to lodge an objection to the winner.

"We'll obviously send a report from here and they will look into the matter."

The BHA issued the following statement: "The incident at Great Yarmouth has been referred to the BHA's head office in order that we can carry out an investigation, in accordance with our rules.

"Since we introduced the microchipping identification system an incident such as this is, as far as we are aware, unprecedented.

"The issue had not been established until after the result had been made official. After the weighed in has been declared on the racecourse, the result cannot be amended by the stewards.

"The responsibility lies with the trainer to present and run the correct horse in the race. Having said that, and while we have not seen an incident of this nature in recent times, we will of course determine what steps need to be put in place to prevent it from happening again.

"We sympathise with the betting operators and betting public who have potentially been affected by this incident."

A host of bookmakers are paying out on the second-past-the-post, Fyre Cay.

"If you backed Fyre Cay @coral in the Yarmouth mix-up race, you will get paid out. Another fine mess," tweeted Coral spokesman David Stephens.

Paddy Power said: "We are paying out on '2yo!' Mandarin Princess and odds-on 2nd FyreCay in the 140 Yarmouth and voiding all losers."

Sky Bet tweeted: "We are paying out on Mandarin Princess AND Fyre Cay in Yarmouth's 4.10. Take Shelter has been settled as runner-up."

PA Media