Experts at the Met Office have issues a Level 3 heatwave warning for parts of the UK - just one step away from declaring a national emergency.
There is now a 90 percent chance of heatwave conditions between Monday and Friday this week.
The amber warning is issued when threshold temperatures for one or more regions have been reached for one day and then the following night, with the forecast for the next day indicates a 90 percent chance of the threshold being met.
This stage requires social and healthcare services to target specific actions at high-risk groups.
The Met Office has issued advice which includes staying out of the sun, keeping your home as cool as possible, taking in plenty of fluids and taking special care of older or vulnerable people.
The warning currently covers the East, Southeast, West Midlands and East Midlands.
Yorkshire and the Humber remains at a Level 2 warning, along with the Southwest, but this could change as the week progresses.
The heatwave is being dubbed the 'Mediterranean melt'.