Britons are being urged to stay inside during the hottest points of the day and keep hydrated as the country faces soaring temperatures.

The UK Health Security Agency has issued a level 4 heat-health alert – described as an “emergency” – while the Met Office has issued the UK’s first red extreme heat warning, with both running from Monday to Wednesday.

Some schools have said they will close amid the hot weather, while train companies urged people not to travel on Monday and Tuesday.

Additional contingency support for ambulance services, such as more call handlers and extra working hours, have been put in place to cope with the strain.

11.30am

At the Royal Botanical Gardens Kew, west London, the temperatures inside the greenhouses are cooler than outside during the heatwave.

On hot, dry days the evaporative cooling effect created by misting the plants in glasshouses can be sufficient to cool the house slightly below external temperatures.

11.25am

These beachgoers avoided the heat by heading out early.