Hot weather can be dangerous, especially for the very young or very old or those with chronic disease. The Met Office say that there is a 80% probability of Heat-Health criteria being met between 0900 on Wednesday and 2100 on Friday.
A weather forecaster said:
"Temperatures are expected to climb significantly this week, with good confidence for a period of hot weather between Wednesday and Friday.
"Temperatures exceeding 30 Celsius are expected quite widely, especially in central, southern and east England, although most coasts will be less hot.
"Fine, sunny conditions on Wednesday, with just the chance of isolated thunderstorms in the far north.
"Thursday is similar, but a greater risk of thunderstorms breaking out in parts of the north and west later.
"Friday may see a more general risk of thunderstorms across England. A transition back to fresher, more changeable weather currently looks likely over next weekend, although there is uncertainty in the detail at present."
Advice on how to reduce the risk either for yourself or somebody you know can be obtained from the Heatwave Plan for England webpage, from your doctor or local chemist, or ring NHS 111.