The Jockey Club is 'seriously concerned' about next month's clash between the Dubai World Cup and the Hong Kong Derby, which it admitted yesterday could deprive the big meeting at Sha Tin of several high-profile riders for at least part of the day. The jockeys affected include Robbie Fradd, who is to ride Fairy King Prawn in Dubai, plus a clutch of European-based riders who are due to end their Club jockey stints on Derby day. That group includes Mick Kinane and Craig Williams - who are likely to have rides in Dubai for their main trainers in Europe, Aidan O'Brien and Mick Channon respectively - and Johnny Murtagh, who has been lined up to partner Daliapour for Ivan Allan. The clash has also created a major logistical headache for trainers, owners and officials who want to attend both racedays. Along with the jockeys, they will face a race against time to make it back from Dubai for the Derby meeting. The Dubai event concludes with the World Cup at 9.15pm local time (1.15am in Hong Kong), and a Cathay Pacific flight is scheduled to leave Dubai at 10.20pm, arriving in Hong Kong at 12.10pm on Sunday, just 50 minutes before the start of the Derby meeting. Winfried Engelbrecht-Bresges, the Club's director of racing, said: 'We are seriously concerned, but hopefully the jockeys will only miss the first race or two. If there is a delay with the flight there may be a more serious problem with jockey bookings, but at this stage we don't want to force riders to choose between the two events.' The clash arose because the Dubai event was moved forward a week and Engelbrecht-Bresges said he was 'very disappointed' by the change of plan, which came too late to allow amendments to be made to the Hong Kong programme. 'We finalised our programme for this season in April last year, and at that stage the Emirates Racing Association had indicated to us that the World Cup would be held on March 31, and so we set the Derby for a week earlier. Last summer, they informed us that Sheikh Mohammed had changed the date, but by then our planning was too far advanced to change things here.' He added that a range of options had been discussed, including moving back the Derby programme by an hour to start at 2pm and hiring a private jet to fly the jockeys back. 'A 12- or 14-seater jet would cost US$120,000, but the Club does not feel obliged to bear the cost. And rearranging the time of the meeting is not easy because it would affect TV coverage on what is a big day for Hong Kong racing.' Engelbrecht-Bresges said he would not attend the World Cup, even though the Club usually has a high-profile presence at the meeting in a bid to attract runners for the following month's Queen Elizabeth II Cup at Sha Tin. 'I cannot miss such an important day here,' he said. A stewards' inquiry will be held at Happy Valley today into the fall of work-rider Chan Kwok-leung on the Sha Tin all-weather track on Wednesday. The 25-year-old remains in a critical condition at the Prince of Wales Hospital.