Desert Hero, owned by the King and Queen, will bid to provide the first Royal win in a Classic for nearly 50 years when he runs in the St Leger at Doncaster on Saturday.

The colt, to be ridden by Tom Marquand for trainer William Haggas, is among nine entries for the race.

Frankie Dettori has chosen to ride Arrest, trained by John and Thady Gosden, rather than stablemate Gregory.

It will be his final British Classic before retiring later this year.

Desert Hero, who gave King Charles his first Royal Ascot winner in June, will bid for victory a year after the horse's breeder Queen Elizabeth II died.

She enjoyed the last Royal winner in a Classic when Dunfermline won the Leger in her Silver Jubilee year of 1977.

Course officials hope King Charles and Queen Camilla will be in attendance for Saturday's race and Haggas believes victory for Desert Hero would provide a boost to the whole sport.

"I think it would mean the world to everyone in our industry. We have been fortunate for so long to have such stoic Royal patronage, and anything that can enhance that will be good," he said.

"From that point of view I think 'Racing PLC' will be hoping Desert Hero goes very well and, as much as we all want to win, I think even connections of the other runners would enjoy a victory for the King and the Queen."

Dettori, 52, has opted for Arrest after rain earlier in the week softened the ground at Doncaster.

Kieran Shoemark will ride Gregory, with Oisin Murphy aboard Middle Earth for the Gosdens.

Irish trainer Aidan O'Brien has four runners - Continuous, Tower Of London, Alexandroupolis and Denmark - as he seeks a seventh Leger win while Chesspiece completes the field.

The Leger is the final Classic of the British Flat racing season after the 2,000 Guineas, 1,000 Guineas, the Derby and the Oaks.

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