On Friday the worst of the heat and the humidity is likely to move further eastwards and it will feel a little cooler further west.
Within the red warning area temperatures could peak for some at 37 or 38C.
There is a wider amber warning stretching across the Midlands and East Anglia where temperatures are still likely to reach the low 30s.
Following localised overnight thunderstorms for some across Scotland, Northern Ireland and northern England, there could be further thundery showers through the morning on Friday and for some they will rumble on into the afternoon.
With plenty of heat energy in the atmosphere some of the thunderstorms could produce intense downpours with gusty winds, frequent lightning and hail.
Friday night will be less warm but temperatures in south-east England and East Anglia may still not drop below 20C.
