Temperatures could reach 36C or higher this week, forecaster have said, with possible impacts to railway lines and power networks as the Met Office considers issuing rare amber or red extreme heat warnings.
Parts of the UK are set to see their fifth heatwave of the summer as the country continues to bake in an unprecedented period of dry, hot weather.
Monday will be slightly cooler before temperatures rise again on Tuesday.
“We’ll probably see highs reaching the mid-30s quite widely on Wednesday, and indeed on Thursday too for England and Wales,” Met Office meteorologist Tom Morgan said.
“On Wednesday, probably the Midlands, maybe a little bit further south, the M4 corridor, west of London, up towards the Midlands, is where we might have a small chance of reaching 36C in one or two spots.
“But Thursday at this stage looks the most likely hottest day of the week.
“So 36C is a fairly reasonable probability locally on Thursday and there’s a small chance it could get even higher than that.”
Half of England and all of Wales have been plunged into drought and more regions could be declared when officials meet at the National Drought Group on Monday.
Mr Morgan said: “If it wasn’t for this incredible summer that we’re currently seeing, then we’d be talking about these temperatures as being really, very unusual.
“But of course, we’ve had such an exceptional summer, people have become a bit used to it.
“There is a potential for impacts, so impacts to infrastructure, things like railway lines and power networks, impacts to vulnerable people as well.”
Health officials have warned of the effect on vulnerable people in the upcoming hot weather, with significant impacts possible in health and social care settings and a potential rise in deaths because of the heat.
Yellow heat health alerts issued by the UK Health Security Agency are in place for the East Midlands, West Midlands, South East, South West, East of England, Yorkshire and the Humber, and London.
The alerts continue until 9pm on Tuesday, but may well be extended as the hot weather continues.
Meanwhile, the Met Office is considering issuing rare extreme heat warnings ahead of the scorching temperatures forecast later in the week.