Leading female jockey Hayley Turner is set to retire at the end of the season.
It is understood a combination of injuries and increasing lack of opportunities at the top level are behind the Nottingham-born rider's decision, who is a three-times Group One-winning rider.
Turner, 32, recorded a landmark success when steering the David Simcock-trained Dream Ahead to victory in the July Cup at Newmarket in 2011 and she followed up when Margot Did won the Nunthorpe Stakes for Michael Bell, with whom she started her career as an apprentice.
Simcock supplied Turner with another victory at the top level courtesy of I'm A Dreamer in the Beverly D. Stakes of 2012.
Big-race rides have been hard to come by since then for Turner, who is flying back from Japan and is scheduled to appear on At The Races on Tuesday morning to explain her plans.
Turner captained the Girls team to a famous success at the Shergar Cup at the beginning of August and has been riding at the World All-Star Jockeys challenge at Sapporo racecourse, recording a winner on Sunday.
She tweeted after that win: "Wooohooo....Winner. What an amazing venue with a brilliant crowd. Thank u Japan."
Another notable win for Turner was the 2010 Lancashire Oaks at Haydock on Barshiba - the dam of Golden Horn's recent conqueror Arabian Queen - for David Elsworth in the colours of Jeff Smith.
Newmarket trainer Bell said: "She was with us a long time and has certainly been an ambassador for the sport.
"She was - and still is, as she isn't retiring just yet - an excellent work rider and her input on the gallops has been as important as on the racecourse. She was an excellent time-keeper and a pleasure to have around.
"She rode lots of good winners for us, but I thought her ride on I'm A Dreamer in particular was out of the top drawer, and on a global stage, too - I can't think of anyone that could have ridden the horse better.
"I wouldn't call her a path-finder as such, but she certainly led the way and that ride on I'm A Dreamer really stood out.
"I gather she is going to stay involved in the industry and I'm sure she will have plenty to offer."
Meanwhile, former British Olympic champion Victoria Pendleton finished second in her first ride as an amateur jockey at Ripon.
The 34-year-old, who won two Olympic gold medals, steered Royal Etiquette to second place after being awarded her Category A licence having made her debut in a charity event at Newbury in July.
Royal Etiquette, a 14-1 shot, started slowly but made up ground to move level with the leader Chocolate Diamond.
The pair rounded the home turn well clear and Pendleton took her mount to the front before being beaten by Jordaura at the finish.
