The UK could have its hottest day on record this week, with temperatures forecast to hit up to 41C (106F).
At 16:00 BST it was 38.1C in Santon Downham, Suffolk, making this the hottest day of the year so far after temperatures rose through the day, reports BBC.
The Met Office has issued a red extreme heat warning on Monday and Tuesday in much of England, from London and the South East up to York and Manchester.
The current highest temperature in the UK is 38.7C, in Cambridge in 2019.
The hottest day on record has already been reached in Wales – with Hawarden in Flintshire hitting 37.1C, according to provisional figures from the Met Office.
Scotland and Northern Ireland are also experiencing their warmest days of the year so far with 30.5C recorded in Edinburgh Royal Botanic Garden, and 30.5C in Armagh, County Armagh.
Temperatures above 37C have been recorded in London, Cambridge, Surrey and Suffolk on Monday.
Amber warnings are in place across England and Wales, and parts of Scotland.
Peak temperatures are expected on Tuesday afternoon, with Worksop, Nottinghamshire, forecast to see 41C by the Met Office.
It is the first time the Met Office has issued a red warning since the system was introduced last year.
It means “widespread impacts on people and infrastructure” are expected, with “substantial changes in working practices and daily routines” required.
Overnight temperatures could be in the mid-20s, before cooling on Wednesday.
Some schools have closed early – or chose not to open at all – although the government has issued guidance designed to keep them open. One teaching union said most chose to stay open.
Network Rail said people should travel only “if absolutely necessary” on Monday and Tuesday, with some cancellations already announced, and speed restrictions in place across the network.
LNER will not run services between London and Leeds and York for much of Tuesday.
Jake Kelly from Network Rail explained precautions are being taken to mitigate the impact of the extreme temperatures, but the heat would place railway infrastructure under “exceptional stress”.
Road congestion dropped by up to 10% in London, Birmingham, Bristol and Glasgow on Monday morning, compared with the same time last week, data from satellite navigation firm Tom Tom showed.
The Ministry of Defence said aircraft were using alternative airfields after reports of the tarmac melting on the runway at RAF Brize Norton in Oxfordshire.
Flights have been delayed at Luton Airport, where – due to the high temperatures – a “surface defect” has been identified on the runway, the airport said.
