The Met Office has issued a level three heatwave action amber alert, warning there is a 90 per cent probability of a heatwave in England between this morning and Thursday morning.
An amber alert is triggered when the Met Office confirms threshold temperatures for one of more regions have been reached for one day and the following night, and the forecast for the next day has a greater than 90 per cent confidence level that the day threshold temperature will be met.
This stage requires social and healthcare services to target specific actions at high-risk groups.
"The hot and humid conditions of recent days are likely to continue across southern England through the first half of the week with trigger criteria highly likely to be met," the Met Office said.
"Across the north Monday will be another very warm, with trigger criteria likely to be met in places. By Tuesday though a band of cloud will bring fresher conditions down from the north, and this fresher weather is likely to reach as far south as the Midlands.
The Met Office added: "By Wednesday thundery showers are likely to break out across central and northern parts and while it will still be very warm, temperatures may fall a little short of trigger criteria. Still hot across the south at this stage. By Thursday we are likely to see fresher conditions gradually spread to all parts with temperatures falling below trigger criteria."
Public Health England issued a warning on Friday advising people to take care in the heat over Saturday and Sunday.