Jockey Colin Teague was attacked by a racegoer at Yarmouth races yesterday. He suffered a split lip after being punched in the face on his way to the parade ring before riding Traikey in the Tote Trifecta Stakes.
His assailant was escorted off the track in handcuffs by the local police.
"I think he was the local nutter," said Teague.
Teague, who had no idea why he was punched, later revealed that he would be taking the matter further.
Sue Lamyman, trainer of Traikey, was shocked by the incident. She said: "I was absolutely flabbergasted - it was terrible.
"It should never be allowed to happen again, the man could have had a knife or anything.
"The horse was supposed to go down to the start early and we wondered why Colin was late. When he arrived he was quite shaken.
"I don't know why he was attacked - he's such a likeable fellow.
"If I had seen what happened I would have withdrawn the horse because the lad obviously wasn't at his best. His tooth had been virtually pushed through his lip.
"Apparently the man had tried to get into the stables earlier and had to be ejected."
A spokesman for Norfolk police confirmed a man had been arrested for attacking a jockey at Yarmouth races and was being held at Yarmouth police station although he had not been charged.