The heatwave is expected to see the UK record its hottest day of the year so far this weekend - with temperatures forecast to soar as high as 30C.

The five regions of England under an amber alert - when the heat is likely to impact the wider population, not just the most vulnerable - are:

• West Midlands
• East Midlands
• East of England
• South East
• South West

A further yellow alert - when the weather is likely to impact vulnerable groups such as those with underlying health conditions, or the elderly - is in place for:

• North East
• North West
• Yorkshire and Humber
• London

The alert, issued by the UK Health Security Agency and the Met Office, was in place from 9am on Friday to 9am on Monday - but has now been extended to 9am on Tuesday.

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The system only covers England and provides warnings of hot weather which might impact the health of members of the public - and is designed to assist healthcare workers who are managing periods of "extreme temperatures".

It comes amid fresh thunderstorm warnings with parts of the country predicted to be hotter than Marbella, Ibiza and Tenerife in the coming days as a "plume of warm air" moves in from the South, triggering thundery showers.

Some areas could see more than 60mm (2 inches) of rainfall in just a few hours on Sunday, with a yellow warning for thunderstorms in place for much of the western side of the UK between noon and 9pm.

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A yellow warning is also in place for Wales and south and western England between 2pm and 9pm on Saturday.

Forecasters have warned of the potential for flash flooding.

The thundery showers may continue into Monday particularly in southern and central England as well as in Wales, the Met Office said.