It was the hottest day of the year so far with a scorching temperature of above 34°C - the most sizzling September day in more than 100 years.
The heatwave brought a blistering high of 34.4°C in Gravesend in Kent recorded on Tuesday afternoon. This makes it the warmest September day since 1911.
Temperatures in the Anglia region peaked at 32.1°C in Thurleigh near Bedford and at Writtle in Essex.
Click below to watch a report on the September heatwave by ITV News Anglia's Russell Hookey
The last time temperatures soared above 30°C (86°F) in September was in 2006 in Kew Gardens, which hit 30.5°C (87°F) on September 11, and the highest September temperature recorded was in 1906 when the mercury hit 35.6°C (96.1°F) in Bawtry, South Yorkshire.
Forecasters said the last time they saw September yielding the hottest day of the year was in 1991 on September 1 at Heathrow.
"Temperatures in the South East have created the warmest September day in the UK since 1911.
Click below to watch a report by ITV News Anglia's Kate Prout
The blistering highs recorded in Gravesend and Heathrow mean the areas are hotter than Bangkok in Thailand, the party island of Ibiza and the city ofMarrakesh in Morocco.
Warnings have been sounded by Public Health England (PHE) following the balmy forecasts.
They urge caution over the coming days and nights, and point out the risks to older people, those with underlying health conditions and people with young children.
The Met Office declared a Level 2 heat-health alert on Monday morning - which means there is a high chance that temperatures will hit certain temperature thresholds for at least two days and the intervening night