A member of the public dressed as a jockey had to be escorted from the paddock at an English racecourse where the Queen was in attendance.
The man, believed to be on a stag party trip, was spotted by Newbury's chief executive Julian Thick before the first race on Friday and led out of the ring.
Queen Elizabeth II, celebrating her 91st birthday, was at the Berkshire track to watch Maths Prize, which finished fifth in the third race on the card.
While it eventually appeared to be a case of nothing more than tomfoolery, with the Queen present it was an incident the course could have done without.
"A guy who appeared to be on a stag do tried to walk into the parade ring with the jockeys, but he was politely asked to leave by Julian Thick, who apprehended him," Newbury's head of communications Andy Clifton said.
"There was nothing sinister about it, but when the Queen is here these things need to be taken seriously."
The Queen was not in the area at the time as she was having lunch in the royal box.