Organisers of the Equerry Bolesworth International Horse Show announce with a deep sense of regret and profound sadness that the 16-year-old gelding Sligo Luckyvalier has been put to sleep.
The horse, ridden by Ivy Freeman-Attwood, fell during the cross-country phase of Thursday's Eventers' Grand Prix class.
The horse received expert on-site veterinary assessment and care.
The rider was uninjured.
Nina Barbour, president of the Equerry Bolesworth International Horse Show, said: "We offer our heartfelt and sincere condolences to Ivy, her support team, the Freeman-Attwood family and all connections of the horse."