Britain has recorded its highest ever temperature as the 40C (104F) mark was provisionally broken for the first time, at Heathrow airport.
The previous record, of 38.7C in 2019, fell first when 39.1C was provisionally recorded on Tuesday morning at Charlwood in Surrey, and then 40.2C was reported at Heathrow at 12.50pm, the Met Office said.
The soaring temperatures came after the hottest night on record, and the highest minimum temperature in a 24-hour period was recorded in Kenley in south London, of 25.8C in the 24 hours to 10am on Tuesday.
Firefighters battled a blaze at a beauty spot in the West Midlands, households in the south-east were told to save water by switching off washing machines, and the transport secretary, Grant Shapps, admitted it would take decades to make road and rail infrastructure resilient enough to cope with the heating climate.
Climate experts described the temperature record as a harbinger of rising risks to lives and livelihoods for at least the next 30 years.
Hannah Cloke, a professor of hydrology at the University of Reading, said the record was a “grim milestone” and part of a “slide into unknown territory for humanity as we heat our planet”. She urged “every politician who is calling for a watering down of climate policy to explain their thinking”.
Nigel Arnell, a professor of climate system science at Reading, said emergency heat health alerts like the one in place for much of England could happen every two to three years by the 2050s, and more frequently if the world remains on track for temperatures to rise by over 2C by the end of the century.
Thunderstorms and downpours of up to 50mm of rain are forecast for Wednesday across parts of southern, south-east and eastern England. The Met Office issued a yellow weather warning of potential flooding, lightning strikes and a slight chance of power cuts.
Overnight, firefighters battled a blaze at Lickey Hills country park, near Redditch in the West Midlands. Pictures posted online showed scorched earth and skeletal trees after the fire spread across 50,000 sq metres. Fifteen people were evacuated.
A 14-year-old boy and a man in his 20s are believed to have been the fifth and sixth people to die since Saturday after getting into trouble in water. Scotland Yard said the boy was seen going into the Thames at Hampton in south-west London and went missing, presumed drowned. The man died at Cotswold Water Park.
Another swimmer was missing at sea off Clacton pier in Essex and five others were pulled from the water.
As the east coast mainline closed from Yorkshire to London because of the heat, Shapps said it would take decades to make the UK’s roads and railways fit for the high temperatures seen this week.
“There’s a long process of replacing it and upgrading it to withstand temperatures, either very hot or sometimes much colder than we’ve been used to, and these are the impacts of global warming,” he said.
Network Rail said the temperature on a rail in Suffolk was recorded as 62C on Monday. No trains were running into or out of London King’s Cross on Tuesday, and no Thameslink or Great Northern services were planned to run north of the capital all day.
East Midlands railway services were stopped between lunchtime and 7pm on Tuesday, while services were disrupted on the west coast mainline, on West Midlands railway and on Chiltern railways.
The tarmac of the A14 in Cambridgeshire buckled to resemble a “skate park”, police said.
Road congestion was again down in Britain’s major cities as millions of people worked from home and some schools remained closed until Wednesday. The supreme court in London, which was refurbished only 13 years ago, closed to visitors on Tuesday because of the heat and an air-conditioning fault.
But amid signs that days of public health warnings may have worked, London ambulance service (LAS) said it had received only a slight increase in 999 calls for fainting and heat exposure on Monday, and ambulances did not have to wait outside hospitals any longer than usual.
Boris Johnson, who on Monday was accused by Labour of “checking out” of his job, told the cabinet on Tuesday that “we should keep schools open and our transport system going as far as we possibly can during these high temperatures, and keep our fantastic NHS providing for the people of this country.”
A spokesperson said: “With temperatures setting records in this country, the PM said no one could doubt we were right to be the first major economy to go for net zero.”
As demand for water surged, households in parts of Surrey, Kent, Essex and Hertfordshire faced low water pressure. Affinity Water told customers around Harlow and Bishop’s Stortford to use water only for drinking, washing and cooking and to avoid using washing machines, dishwashers and hosepipes.
Two villages in Kent – Challock and Molash – have been without water since Saturday because of high demand and a power outage at a water treatment station, and South East Water has set up a bottled water station.
“Water companies are seeing unprecedented peak demand for water during this extreme hot weather event. We are urging everyone to carefully consider the amount of water they are using at this time,” said a spokesperson for Water UK. It has asked people to only water plants with watering cans, let lawns go brown and stop washing cars.
Farmers said crops that would not normally demand irrigation now needed it, while reservoirs were running low. “The lack of rain has severely hampered grass growth which could hit feed supplies for the winter, adding additional costs to livestock farming,” said Tom Bradshaw, the deputy president of the National Farmers’ Union.
