Letterkenny jockey Martin Harley has been taken to hospital following a heavy fall aboard Red Art at Lingfield.
The incident happened when Harley was riding the 7-4 favourite Red Art in the Ladbrokes Mobile Handicap.
The pair were closing on the leaders inside the final furlong when Red Art clipped the heels of horses in front of him.
The horse fell heavily and suffered fatal injuries. Harley was thrown hard to the ground and had to be taken to East Surrey Hospital in nearby Redhill.
It was to cause a delay of nearly an hour and a half to wait for the ambulance before the remaining events were rushed through.
Presumido (5-1) held on to win the race, by half a length from Alnoomaas, and the trainer Simon Dow said: "It's a hollow victory when something like that happens, and our thoughts are with Martin and the other connections."