Researchers are uncovering a link between rising temperatures and hyponatremia, a condition caused by a dangerous decline in sodium in the body.

Heat-related illnesses can affect anyone. Officials say prolonged exposure to extreme heat without relief can cause health issues ranging from mild to severe and, in some cases, even death.

Temperatures of up to 34C are forecast today, with the country's hottest spots expected in the Midlands and south Wales.

The London Fire Brigade says the risk of wildfires in London is "severe", with warnings in place across the country.