Weather forecasters are predicting temperatures topping out at 35°C or 95°F on Saturday in the Anglia region as Europe's heatwave spreads into the UK.
The heatwave will be short-lived lasting one day only as East Anglia stays warm on Sunday but is also a lot fresher.
The Met Office says temperatures as high as 35°C are very unusual in the UK and have only been recorded on a few occasions.
The record June temperature in the UK is 35.6°C at Camden Square, London on 29 June 1957 and then equalled in Mayflower Park, Southampton on 28 June 1976.
A number of locations in the Anglia region had already exceeded 21°C but 9am which is higher the average June maximum temperature.
On Friday, France broke its all time temperature record when it reached 45.9° / 114.6°F.
The UK's highest recorded temperature is 38.5°C / 101.3°F at Faversham in Kent on 10 August 2003.
During the famous UK summer heatwave of 1976, the 35°C temperature barrier was broke somewhere in the country every day from the 25th to the 28th.
The rising heat is in part due to warm air originating from northern Africa that has brought a scorching heatwave to a large swathe of Europe.
NHS England and emergency services have issued warnings to the British public to take care in the hot conditions.
England's most senior nurse called on the public to help children, the elderly and other vulnerable people at risk of being affected by the heat.
Ruth May, chief nursing officer for England, said: "Like lots of people I'm looking forward to having fun in the sun with family and friends this weekend, but nobody wants to spend a pleasant day stuck in a hospital or urgent treatment centre."
Temperatures at 9am in East Anglia
21.4°C at Higham near Bury St Edmunds, Suffolk
21.3°C in Braintree, Essex
21.3°C in Wattisham, Suffolk
21.2°C in Writtle, Essex
21.1°C in Weybourne, Norfolk