Dozens of people required medical assistance because of heat-related illness on the second day of Royal Ascot, racecourse officials have confirmed.
The event attracted over 41,000 spectators on Wednesday, during which temperatures reached 29.7C (85F).
A Royal Ascot spokesperson said one person was taken to hospital while a further 42 received treatment on site.
Free water is being provided to all those attending, the spokesperson added.
They also said additional gazebos and parasols had been installed.
Horses are kept cool using misting fans and a mobile water bowser with a 1,000-litre (220-gallon) capacity.
In total, more than 250,000 people are expected to attend the five-day event, which ends on Saturday.
The event was founded by Queen Anne in 1711 and is now well known as a key social occasion, as well as a sporting event.
