In short, the most successful female jockey in Britain is Hayley Turner OBE who, at the last count, had ridden 834 winners. Turner rode her first winner on Generate, trained by Mark Polglase, in an apprentice handicap at Pontefract on June 4, 2000. Five years later, at the age of 22, Turner became the first female Champion Apprentice, albeit jointly with Saleem Golam; her grand total of 60 winners was more than enough to see her past the 95 required to ride out her claim.
Thereafter, Turner has recorded several notable ‘firsts’ in her long, illustrious career. In 2008, she became the first female jockey to ride a hundred winners in a season. Three years later, she became the first female jockey to ride a Group One winner, when partnering Dream Ahead, trained by David Simcock, to victory in the Darley July Cup at Newmarket in July, 2011. Turner retired from riding at the end of the 2015 season but, shortly after being awarded an OBE for services to horse racing in June, 2016, briefly returned to the saddle to ride for the ‘Girls’ team in the Shergar Cup at Ascot.
Thereafter, Turner pursued an abortive career as a television presenter before returning to riding, full-time, in 2018, at the age of 35. In 2019, she became just the second female jockey, and the first for 32 years, to win a race at Royal Ascot.
On 10th April 2021, Rachael Blackmore won the Aintree Grand National on Minella Times; the first female jockey to ever do so. This was off the back of a Champions Hurdle win at the Cheltenham Festival (also becoming the first woman to win the Ruby Trophy for leading Cheltenham jockey in the process). As such Rachael Blackmore certainly has a claim to be called the most successful female jockey in Britain.