Donnacha O'Brien: Jockey retires from saddle aged 21
Classic-winning jockey Donnacha O'Brien has announced he is quitting the saddle at the age of 21.
O'Brien is the reigning champion jockey in Ireland after securing the title for the second successive year, with 111 wins in 2019.
He retires with 10 top-level wins, including consecutive 2,000 Guineas victories with Saxon Warrior and Magna Grecia.
He will follow his father Aidan and brother Joseph into the training ranks.
O'Brien's final Group One success came aboard Magical in the Champion Stakes at Ascot in October.
"After thinking about things for a while, I have decided to concentrate on training next year," he said in a statement on Twitter.
"Riding has been very good to me and I owe everything to the people around me."
Cornelius Lysaght, BBC racing correspondent
Donnacha O'Brien has achieved a large amount in a short time, and the successes were not down to nepotism and his family's quality horses - though I do recall him saying at Newmarket, after the first of two successive 2,000 Guineas wins, on Saxon Warrior in 2018, that it was what people would say.
But actually they observed a sharp racing brain and a terrific record achieved despite him being 'too tall' and therefore having to observe a strict regime to achieve the correct weights.
Had that not been the case, he could have been around at the top for some time.