There are growing concerns that people’s lives could be at risk as the Met Office says there is a chance that a new UK record temperature could be set as early as next week.
Meteorologists say there’s an 80% chance mercury will top the UK’s record 38.7 degrees Celsius (101.7 degrees Fahrenheit) temperature set in Cambridge in 2019.
The heatwave is set to peak on Tuesday, with temperatures soaring over the weekend.
The Met Office has issued an amber heat warning covering much of England and Wales from Sunday until Tuesday.
Daytime temperatures on Saturday are predicted to be around 27C (80.6F) in London, 26C (78.8F) in Cardiff, 23C (73.4F) in Belfast and 21C (69.8F) in Edinburgh. On Sunday it could hit 30C (86F) in the capital, 27C (80.6F) in Cardiff, 24C (75.2F) in Belfast and 23C (73.4F) in Edinburgh.
Temperatures are expected to rise further across the country on Tuesday and reach the mid-30s in much of England and Wales.
There is a 50 per cent chance of temperatures reaching 40C (104F) somewhere in the UK, with the Met Office issuing the first red warning of extreme heat.
The UK Health Security Agency has increased the heat health warning from level three to level four – a “national emergency“.
Level four is achieved “when a heatwave is so severe and/or prolonged that its effects extend outside the health care and social systems… At this level, disease and deaths can happen to healthy and well-to-do people, not just high-risk groups,” it said.
The Met Office’s red alert for Monday and Tuesday covers an area from London to Manchester, and to the Vale of York.
Met Office spokesman Grahame Madge said: “If people have a vulnerable relative or neighbour, now is the time to make sure they are taking the right measures to be able to cope with the pandemic. hot weather because if the forecast is correct as we think, in the red warning zone, people’s lives are threatened.
“This is a very serious situation.”
Train operators warn passengers to avoid anything but a ‘necessary’ trip
A No 10 spokesman said rail speed restrictions may be needed for “some parts of the network next week to manage hot weather and avoid any potential damage”.
Jake Kelly, of Network Rail, warned journeys would be “significantly longer and potentially delayed as a result of speed restrictions put in place to keep passengers and rail staff safe”.
Train operators have warned passengers to avoid anything but “really necessary” travel on Monday and Tuesday.
Several schools across the south also closed on those days.
Motorists have been advised to take their trips outside of the hottest parts of the day, especially if they have older cars.