A spokesperson for the RSPCA has confirmed to the Sunday Tribune that the society's equine consultant David Muir made an attempt to get in contact O'Brien during the week but the Ballydoyle trainer was unavailable.

The spokesperson was at pains to point out that O'Brien is not under investigation and that this is simply part of the process undertaken by the RSPCA when a member of the public makes a complaint, as happened in the wake of Horatio Nelson's death. "This isn't an investigation or anything like that.

We want to try and find out what happened and whether or not steps can be taken in the future to prevent it happening again." The complaint to the RSPCA came in the wake of the decision to run the horse even though there appeared to be something his jockey Kieren Fallon was unhappy with before the start of the race. Muir told BBC Radio that he would be studying the tape of the race.

"I think that in a circumstance like that, " he said, "where something shows up in a horse's make-up just before a race that isn't part of its history, perhaps we should be looking at making it mandatory that the horse be withdrawn. I'm not trying to be critical towards anybody.

Kieren Fallon is a good jockey who is renowned for welfare and we also had a top trainer and a very experienced vet. They made a decision and, sadly, that decision went wrong."