The former champion jockey Kieren Fallon is once again facing a potentially crippling blow to his career after a positive drugs test in France earlier this year.

On Friday, racing's most controversial figure walked free from the Old Bailey in London after the collapse of a race-fixing trial. But less than 24 hours later came confirmation that Fallon tested positive for a drugs test carried out at Deauville on August 19th.

The jockey is now awaiting the results of a B sample. Initial reports suggest the positive test is for cocaine and Fallon only returned last June from a six- month worldwide ban after testing positive for the same drug in France in July of last year.

A second offence is likely to result in an even longer ban this time and Fallon, and his Coolmore Stud employees, are anxiously awaiting the results of the crucial B sample.

There has already been speculation that this latest blow will see Coolmore's patience finally run out with their enigmatic number one jockey although significantly, champion trainer Aidan O'Brien appeared to be supportive of his wayward jockey yesterday.

Speaking in Hong Kong, O'Brien said: "Kieren, everyone knows, has an addiction problem and he had it before he came to us. Anybody like that deserves help. Everybody has always helped him, they've stood 100 per cent behind him all the way, and I can't see why it would be any different."

French racing's ruling body, France Galop, has confirmed the initial positive test on the day that Fallon rode Myboycharlie, owned by the Coolmore Stud syndicate, to win the Group One Prix Morny last August.

Initial reports suggested that Fallon could be banned from racing worldwide for up to 18 months, based on the experience of another Irish jockey, Dean Gallagher, who was banned for a year and a half following a second positive cocaine test in 2002.

However, a Turf Club spokesman in Ireland indicated yesterday that such a penalty is not automatic.

"If there was a second offence in Ireland there would be no set penalty," said the Turf Club chief executive Denis Egan.

"Every jurisdiction is different but the French will have to hold a hearing, and if the B sample is positive I'm sure they will hold the case on its merits. But the fact he has already had a suspension won't help matters."

This is just the latest twist in Fallon's colourful career which appeared set to get back on track after the collapse of the race-fixing trail on Friday.