Arc pain again for Frankie Dettori as injury ends his season

... while Sheikh Mohammed calls up Lord Stevens for new drugs inquiry

Frankie Dettori is helped to return to the medical room at Nottingham yesterday after a fall left him with a fractured ankle (PA)

Frankie Dettori will miss the ride on the unbeaten second favourite Treve in the Prix de l'Arc de Triomphe on Sunday after being ruled out for the season with a fractured ankle, suffered in a fall at Nottingham.

The jockey's business manager, Peter Burrell, said: "It's bad news. He went to Cambridge Hospital and X-rays found he had suffered a fractured ankle. He was extremely disappointed on the phone and did not want to discuss it much more than that. It's an extremely painful injury. Sunday is out – as is the season."

Treve will now be partnered by Thierry Jarnet, who rode her to victory in her first three races before she was sold to Dettori's new employer, Sheikh Joaan al-Thani. The former champion jockey gained an impressive win on the three-year-old in the Prix Vermeille at Longchamp last month, his first big-race success since returning from a drugs ban in the summer. He has ridden just 17 winners in Britain, including the opener at Nottingham, with a strike rate of only 8 per cent.

Last year's Arc brought Dettori's rift with his former employer Sheikh Mohammed into the open when he rode Ballydoyle's Camelot and that was swiftly followed by the failed drugs test that cost the jockey a lengthy ban. The sheikh has been no stranger to woes himself in the meantime and has called on Lord Stevens, the former Metropolitan Police Commissioner, to conduct an internal inquiry into his global racing empire. This comes in the wake of the Godolphin steroids scandal and the more recent seizure of veterinary products, some unlicensed, at a training centre for endurance horses in Newmarket in August and from a Dubai Royal Air Wing flight at Stansted airport in May.

Lord Stevens said the inquiry, which is likely to last into the new year, would examine "practices at all of the major components of Sheikh Mohammed's equestrian properties and operations. Sheikh Mohammed is adamant that any evidence of violations of law or regulation in any jurisdiction should be shared with the appropriate authorities. Our primary focus is on preventing any future systemic failures."