The six-times champion tested positive for a banned substance after the win of Myboycharlie in the Prix Morny at Deauville.

His solicitor, Christopher Stewart-Moore, said: "I had a letter at the weekend that confirmed the positive findings. "The letter tells me that the Medical Commission wish to meet in January to consider the case. I have instructed our French legal counterparts to request all the relevant data before we decide on our next step."

Fallon - recently acquitted along with five others of conspiracy to defraud by a jury at the Old Bailey - has previously served a six-month suspension imposed by France Galop for testing positive for a metabolite of a prohibited substance in June 2006.

He was suspended from December 7th, 2006. As the Irish Turf Club, under which he is licensed, have an agreement with other racing jurisdictions to reciprocate bans of this nature, he was also unable to ride here. Jump jockey Dean Gallagher was banned for 18 months by France Galop when he failed a second drugs test in 2002.

Meanwhile, Hardy Eustace will face a maximum of 14 rivals in the BGC Long Walk Hurdle at Ascot on Saturday. Dessie Hughes's dual Champion Hurdle winner will attempt this three-mile-one-furlong trip for the first time in his career, with the outcome likely to determine his Cheltenham target.

Paul Petrie, totesport spokesman said: "Dessie Hughes has suggested that Hardy Eustace could still go down the Champion Hurdle route, but a good performance on Saturday may change his mind. He is certainly the horse to beat."

Chief opposition is likely to come from Jonjo O'Neill's Black Jack Ketchum, who returned to winning ways at Wetherby but was denied a run in the Long Distance Hurdle at Newbury because of soft ground.