Olympic gold medallist Cian O'Connor was embroiled in a second doping controversy last night after it emerged that another horse he used in competition prior to the Olympic Games also tested positive in a drugs test.
Last night, however, Mr O'Connor insisted he had not cheated and that both horses received a sedative for injuries at least a month before taking part in any competition.
ABC Landliebe, the mare that provided Mr O'Connor with a string of speed class wins this season, tested positive at the Italian Nations Cup show in Rome last May.
The horse on which he won his gold medal in Athens, Waterford Crystal, tested positive for the same substance, Mr O'Connor told The Irish Times last night.
Mr O'Connor said there was "no malice" involved and that the sedative appeared to have shown up in the tests because of new sensitive testing methods.
"I wouldn't sedate a horse to try and get it to jump better. If you want a horse to go better you'd use some kind of other medicine. You wouldn't go and put him asleep. This is a routine treatment and it just doesn't add up," he said.
He said he had been advised by his vet, Mr James Sheeran, that the sedative would be out of the horse's system within 10 to 14 days.
"It's James's common practice that he treats the horse with a mild sedative. There's nothing sinister or untoward about this. It wasn't a case of 'we'll take a chance'. These were minute amounts," he told The Irish Times.
"In James's opinion the horse would have the effect for a couple of days and it would be out of its system within 10 to 14 days. Treatment at the time of rest has nothing to do with making them jump." Mr O'Connor said he only received details of the positive test results for ABC Landliebe last Thursday, the same day he received Waterford Crystal's positive results.
Mr O'Connor is facing a long fight to hold onto his medal after a second sample taken from Waterford Crystal is officially sent for confirmatory analysis.
A second positive test would result in automatic disqualification and the loss of Ireland's only medal from the 28th Olympiad. That procedure is expected to take up to three weeks, after which Mr O'Connor will be given 10 days to prepare a case to present to the judicial committee of the international equestrian governing body, FEI.
Mr Sheeran told The Irish Times last night that he had done nothing wrong and he had been using the same tranquillising agent for "years and years" without any problem.
"I felt extremely safe giving this medication. I didn't feel there was any possibility that any traces would be found. The therapeutic value of the sedative lasts only a few days," he said.