Fallon rides out to meet his destiny with Dylan

It is a very strange state of affairs, but not an unfamiliar one. Two years ago, when Kieren Fallon won this same race, he did so knowing that he had to answer bail the very next morning. And a few months later, after he won another great prize on this same horse, he was again required to fly to London and present himself at a police station. On that occasion, Fallon was told that he would have to stand trial. Now, 15 months later, the two greatest challenges of his life – one that captivates him, one that menaces him with destruction – have again converged to create still greater melodrama.

Tomorrow Fallon rides Dylan Thomas in the Prix de l'Arc de Triomphe at Longchamp. At 42, his esteem for both the horse and the race would certify success as perhaps the consummating moment in a career embracing six riding championships. Then, on Monday morning, he will sit behind a glass screen in the Old Bailey and listen as the prosecution counsel finally begins to specify the allegations against him.

Along with five other defendants, including two lesser jockeys, Fallon denies a charge of conspiracy to defraud punters. Whatever the outcome of the trial, it will surely prove traumatic for racing. How poignant, that its central character should have this chance to demonstrate what is at stake – not just one of the great riding talents of the modern era, but also the reputation of a sport that hardly needs this kind of excruciating sub-plot to guarantee suspense.

For this is one of the great sporting occasions. The Arc should reveal the champion thoroughbred of Europe, and brings together many men and horses who deserve better than to be reduced to mere supporting actors by this sensational script. The hot favourite is Authorized, a brilliant Derby winner, ridden by Fallon's natural foil, Frankie Dettori. His trainer, Peter Chapple-Hyam, has come back from a professional abyss and confirmed himself the man best qualified to resist the mastery of Aidan O'Brien. And as trainer of not just of Dylan Thomas, but of three other runners, O'Brien himself also deserves a share of top billing, as he seeks one of the few great races still to elude him.

But the fact is that this could be one of those rare occasions in racing when destiny shows its hand with a candour verging on coarseness. For as luck should have it, at the odds, Dylan Thomas looks a pretty sound bet.

Though he scarcely needed to raise the stakes, Fallon recently described this horse as the best he has ridden. Admittedly many were rather taken aback by that judgement. Dylan Thomas has been repeatedly, if narrowly, thwarted over 10 furlongs, notably by Manduro at Royal Ascot in June, and Authorized at York in August. But he has been given very few opportunities over this longer distance, which almost certainly suits him best. In fact, he has gone a mile and a half only three times. Last year, he was caught on the line in the Derby and then romped away with the Irish version; and in July he outclassed his rivals for the King George VI and Queen Elizabeth Stakes at Ascot. Since then he has again dropped back in trip; at York giving Authorized a head-start on ground that suited the younger colt better, and then winning at Leopardstown.

Regardless of distance, he would have no chance in soft going, which seemed likely earlier in the week. But the weather has turned in his favour and conditions could come right by tomorrow. Conversely, O'Brien's other big hope, Soldier Of Fortune, produced much his best performance in heavy ground.

It is conceivable, in fact, that Yellowstone – unconsidered at 100-1 – might outrun Soldier Of Fortune on good ground. Yellowstone did not show his form in New York last time, but had previously seemed to be improving with racing.

Soldier Of Fortune did manage to beat Zambezi Sun in their trial on good ground over course and distance last month, but the best of just four French candidates – cruelly shorn of the injured Manduro – was rusty that day and is expected to narrow the gap this time. Neither colt, however, has so far matched the form of Authorized, whose generous effort at Epsom probably accounted for his subsequent submission at Sandown. He bounced back with an unequivocal performance at York, Chapple-Hyam has freshened him up again since, and his rider is peerless at this awkward track.

Dylan Thomas has certainly had a harder season, and Authorized would be hard to resist in soft ground. Strictly in terms of value, however, there is far less between the pair than the odds imply. If the ground does keep drying out, the stage will be set for Fallon.

Rest assured, he will not be distracted by the floods breaking upon his career. He has always been as icily detached as Dettori is frothily engaged. His first Arc winner, in 2005, was Hurricane Run, like Dylan Thomas owned by John Magnier and his partners in Coolmore Stud. These men have stood by Fallon throughout this extraordinary purgatory, even though his prohibition from British racecourses – which can be considered contentious at best, brazenly inequitable at worst – has required them to find replacements in many vital races. But they can still use him in Ireland, and here in France. Hence his opportunity now, hence his cue.

Fallon's trial is expected to last four months. On this gilded autumn weekend, he can keep a gloomy, looming winter in abeyance. Yet even triumph would be flavoured with heartbreak. In the words of Dylan Thomas himself:

'My ark sings in the sun
At God speeded summer's end
And the flood flowers now.'