Heat-health alerts have been upgraded for much of England amid warnings of temperatures of 32C (89.6F) midweek.
There is an amber warning in eight of the country’s nine regions until Sunday – only the North East has a yellow one.
The United Kingdom Health Security Agency’s amber alert means people of all ages could be affected, putting the NHS at risk.
Hot conditions will be also felt in Wales, while parts of Scotland and Northern Ireland could see “unseasonably high temperatures”.
English regions included in the amber warning are: London, the South East, the South West, the East and West Midlands, the East, North West and Yorkshire and Humber.
All eight were issued with a yellow warning yesterday but this has now been upgraded.
It also means officials do not believe there will be a significant impact on the NHS in the area.
Temperatures reached 30C yesterday in southern England and south-east Wales, according to the Met Office.
The hot weather comes after what has generally been regarded as a cool wet summer for much of the UK.
While July in particular was wetter and cooler than average with the maximum temperature failing to regularly reach 20C, the previous month was the UK’s hottest June on record.
The warm conditions are continuing through Tuesday, with highs of 31C expected near London.
