British jockey Paul O'Neill apologized Tuesday for head-butting his horse at a race last weekend. The Horseracing Regulatory Authority is holding an inquiry after reviewing TV footage of the incident at the Stratford races on Sunday. "I would just like to say to the public that I'm very sorry they had to see such a thing," O'Neill said in a statement. "I've never done it before and it will never happen again." City Affair was being unruly in the parade ring, ultimately throwing O'Neill. The jockey got to his feet and grabbed the reins, pulling the horse to him, before lowering the butt of his helmet into it. "When I got to the start he headed straight for a car with me, stopped five feet from the car, whipped round and dropped me," O'Neill said. "I landed on my feet, but a bit awkwardly for my knee and I was a little bit angry then, but I've never done anything like this before and I'm glad to say the horse is OK after it." "Angry jockey does a 'Zidane' to his horse," read the headline of London's Evening Standard, referring to French soccer star Zinedine Zidane's infamous head-butt in the World Cup final. City Affair went on to finish fourth in the two-mile event. O'Neill was given a caution by stewards for his use of the whip in the race. O'Neill's actions will be reviewed at an HRA disciplinary hearing on Aug. 3, where he is expected to face a fine and short ban. The 26-year-old O'Neill, who has ridden 51 winners, was questioned by the HRA over his ride of a novice hurdler in March.