The heat will ease on Wednesday, with a chance of thunderstorms, especially in the southern half of England, and it will be wet over much of Scotland and northern England for a while, according to weather experts. This is because the rise in mercury levels has led Transport for London (TfL) to advise passengers to travel only for “essential journeys”.
The Met Office’s forecast after the heat spikes reads: “Scattered showers are likely to develop in some places.
“Over the weekend, there could also be daytime showers and maybe longer showers.”
For Monday and Tuesday, rail passengers in England and Wales were warned to travel only when necessary, and Network Rail said speed limits were likely.
The TFL tweeted: “Travel only if it is essential due to the forecast of very high temperatures.”
Some schools will also close early next week and some hospital appointments will be cancelled.
The rest of England, Wales and southern Scotland receive an orange warning of extreme heat – while deadly wildfires have broken out in Europe in Portugal, Spain and southwestern France.
According to the UK Health Security Agency (UKHSA), a national emergency is declared when a heat wave is so severe and/or prolonged that its effects extend beyond the health sector.
Transport, food and businesses could also be affected, and it could cause power or water shortages, according to the agency tasked with protecting the population from health threats.
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Mr Barclay said: “The clear message to the public is to take sensible steps in terms of water, shade and cover. That is the best way to combat the heat.
“We’re asking people to keep an eye out for their neighbors and those who may be vulnerable.”
The Met Office described the predicted heat coming from France and Spain as “absolutely unprecedented” and urged people to treat it as a storm warning and consider changing plans.