Amber heat health alerts have been issued by the UK Health Security Agency (UKHSA) with a potential heatwave set to develop this weekend.
The amber alerts cover the east, south-east and south-west of England as well as London, and are valid from 12:00 BST on Thursday until 20:00 on Tuesday.
Yellow alerts are valid across the Midlands during the same times.
Temperatures are set to climb above 30C (86F) during Friday and then again from Sunday – with the potential that some locations in the south and east of the UK may enter official heatwave conditions.
Amber heat health alerts are issued when high temperatures are likely to have a significant impact on health and social care services.
They suggest there is likely to be an increase in deaths, especially among those aged over 65 or with long-term health conditions.