The extreme heat warning applies to the East Midlands, East of England, South East England, North East England, North West England, South West England, Wales, West Midlands and Yorkshire & Humber.
The Met Office’s orange warning reads: “A hot spell is likely to develop from Sunday, likely to peak early next week, leading to widespread impacts on people and infrastructure.
“What to expect: There is a high probability that the entire population will experience adverse health effects, not limited to those most vulnerable to extreme heat, which could lead to potentially serious illness or death.
“The government’s advice is that 999 services should only be used in emergencies; seek advice from 111 if you need non-emergency health advice.
“Significant changes in work practices and daily routines will likely be needed.” Significantly more people are likely to visit coastal areas, lakes and rivers, leading to an increased risk of flood risk management incidents. “Delays on roads and road closures are possible, along with delays and cancellations of rail and air travel, with the potential for significant welfare problems for those experiencing even moderate delays.”