Jockey Racheal Kneller has admitted she is “totally gutted” after being forced to retire from the saddle.
The 34-year-old has been sidelined since suffering concussion in a fall in February of last year.
Kneller, who rode 47 winners in Britain, had hoped to make a comeback but has been advised not to return to race-riding.
In a statement posted on Twitter, Kneller said: “I’m devastated to make this decision, but I won’t be returning to the racecourse. The symptoms causing me to fail a concussion test needed for racing, have sadly not improved.
“My specialist said I won’t race this year, with no certainty that I will have made any further improvement next year either. I need to accept that the effects on my head trauma may well be permanent now.
“I am totally gutted, but I feel extremely lucky that it wasn’t worse. I can still ride horses, which is a huge relief!
“Horses are my life and have been since I could walk. I have five here at home to keep me busy, three of which are ex-racehorses – Yorkhill, Ruacana and Titan Diamond.
“I’m not sure what the future holds for me career-wise, as racing has consumed my life for 15 years. Your brain never stops and you never get a break from it, so the change will be strange for a while.
“I want to thank Oaksey House and Dr Jerry Hill for their support during my recovery. Also my bosses Jamie Osborne and Mark Usher who helped me so much in my early days. James Bennett too, who has stood by me from day one and provided me with endless support and loyalty – and 11 winners aboard his superstar Idol Deputy.
“I also can’t thank every trainer and owner enough for having me aboard your horses and allowing me to live my dream for the past 15 years. My family and friends have also been so supportive throughout my whole career – and finally, my partner Ben. He has been my absolute rock and made the difficult periods so much easier.
“It’s been a career I’m so proud of and I’ve accomplished so many goals I set when starting out that I can go out with my head held high.”