A heatwave fuelling ferocious wildfires in Europe pushed temperatures in Britain over 40 degrees Celsius (104 degrees Fahrenheit) for the first time on Tuesday.
After the UK's warmest night on record, the Met Office said 40.2°C had been provisionally recorded by lunchtime at Heathrow Airport, in west London, taking the country into uncharted territory.
Britain's previous all-time temperature record of 38.7°C, set in Cambridge in eastern England in 2019, had already been smashed earlier Tuesday.
Experts blame climate change for the latest heatwave and warn worse is in store in years to come.
"Climate change driven by greenhouse gases has made these extreme temperatures possible and we're actually seeing that possibility now," said Stephen Belcher, the Met Office's head of science and technology.
"These extremes will get more extreme," he added.
The high temperatures have triggered an unprecedented red alert in much of England, where some rail lines were closed as a precaution and schools shuttered in some areas.
Grassland fires erupted on the edge of London, threatening nearby houses.
Meanwhile, all trains were cancelled from usually busy Kings Cross station, leaving many travellers stranded.
"It's a little frustrating," said US tourist Deborah Byrne, trying to reach Scotland.
But with road surfaces and runways melting and fears of rails buckling, Transport Secretary Grant Shapps conceded much of Britain's infrastructure "is just not built for this temperature".
(FRANCE 24 with AFP)
