A potentially serious incident was avoided on the return of horse racing to Newmarket on Thursday when a large plane of glass fell from the main grandstand on to seats below.
Racing was taking place for the first time on the Rowley Mile since the start of lockdown when the bizarre incident happened.
On a normal race day, the seats beneath the Champions Gallery would have been packed with spectators, but on this occasion the fact that racing was being staged behind closed doors turned out to be a blessing in disguise.
PA Racing correspondent Graham Clark, who is one of only two reporters allowed on the course under current safety restrictions, tweeted that the window fell just before the start of first race.
Newmarket is gearing up for one its most important weekends of the year with the 2,000 Guineas taking place on Saturday behind closed doors.
"A window fell out of the Champions Gallery on the third floor on to the level two seating for no explained reason. We are now investigating why and how it's occurred," Amy Starkey, who runs Newmarket as East Regional Director for Jockey Club Racecourses, said.
"Clearly it is very concerning and thankfully we are staging racing behind closed doors so no members of the public or our team have access to the area."