Popular sprinter Captain Dunne has died at the age of 12 after suffering a fatal accident in his retirement paddock.
The son of Captain Rio won 12 races from 100 starts for trainer Tim Easterby and owners Middleham Park Racing and was placed on a further 21 occasions.
The biggest victory of his career came in the Investec Dash at Epsom in 2011.
He his final race as an 11-year-old was at Newcastle last November.
Middleham Park racing manager Tim Palin said: "Bought for 30,000 guineas in 2006, he was our most expensive horse at the time and climbed to a career high rating of 108.
"Tim turned him into one of our first very good horses, winning 12 races and £212,000 in prize-money.
"Named after the Manchester City defender Richard Dunne, his memorable victory in the Investec Dash at Epsom on Derby day in 2011 was a day we will never forget and we thank Tim and the team for looking after him so well for so many years.
"We will forever owe him a huge debt of gratitude for helping put Middleham Park Racing on the map and I am very sad hearing this news. Rest in peace Dunny."