Fires are continuing to ravage through houses and buildings across the UK after temperatures topped 40C in the UK for the first time.
A temperature of 40.3C was provisionally recorded in Coningsby in Lincolnshire yesterday afternoon, beating the previous record for the UK of 38.7C in Cambridge three years ago, by 1.6C.
The UK Met Office said at least 34 observation sites across England have provisionally broken the previous all-time record, from Bramham in West Yorkshire to Charlwood in Surrey.
Scotland has experienced its hottest day on record, with the temperature reaching 34.8C in Charterhall in the Scottish Borders, Met Office provisional figures showed.
Amid the sweltering heat a major incident was declared in London in response to a surge in fires across the capital, nine people have died since Saturday in swimming accidents and there has been widespread disruption to train services.
As temperatures soared, interim deputy chief executive of NHS Providers, Miriam Deakin, said the heatwave was forcing hospitals to scale back the number of planned surgeries.
She said they were installing cooling units to try to cool down IT server rooms.
An East of England Ambulance Service spokesman said the service had seen above-average call numbers since Monday afternoon and it expected to still be seeing an impact from heat-related illness into the weekend.
Road congestion in several cities, including Birmingham, London and Manchester was down today as people heeded advice not to travel, while commuter numbers were also down on the Tube and bus services in the capital.
The record heat came after the UK endured its warmest night on record, with temperatures remaining in the mid-20s in some places.
Sales of fans, ice cream and paddling pools and burgers rocketed as the weather sparked a spending spree on summer essentials, according to retailers, while tech experts urged smartphone users to keep their gadgets out of the sun to ensure they continue working properly.
Heatwaves are being made more intense, frequent and longer by climate change, and scientists said it would be "virtually impossible" for the UK to have experienced temperatures reaching 40C without human-driven global warming.
The Met Office's chief scientist Professor Stephen Belcher warned temperatures would get more extreme in the future, and the only way to stabilise the climate was to cut greenhouse gas emissions to net zero.
The UK is experiencing record heat as much of Europe bakes in heatwaves that are fuelling wildfires in France, Spain and Portugal.
In Ireland, Met Éireann has issued a thunderstorm warning for 13 counties as temperatures in some parts of the country are forecast to reach up to 28C.
For parts of the UK, the searing temperatures come on top of months of below average rainfall, leaving conditions tinder-dry and putting most of England at "exceptional" risk of wildfires, with fire crews battling hundreds of blazes around the country.
On Monday, Essex County Fire and Rescue Service received three times its average number of calls, driven by wildfire reports, while a blaze at Lickey Hills Country Park near Birmingham, spread to around 50,000 square metres and forced 15 people to flee their homes.
London Fire Brigade declared a major incident today as it warned it was battling "several significant" incidents in the capital, with people urged not to have barbecues or bonfires due to the "unprecedented" challenge fire crews faced.
Around 100 firefighters tackled a blaze in the village of Wennington, east London, this afternoon, with television footage showing black smoke billowing into the air, with buildings and fields on fire.
NEW: London Fire Brigade has just declared a Major Incident in response to a huge surge in fires across the capital today.— Sadiq Khan (@SadiqKhan) July 19, 2022
This is critical: @LondonFire is under immense pressure. Please be safe.
I'm in touch with the Commissioner and will share updates when I have them.
Nigel Arnell, Professor of Climate Change Science, University of Reading, said the hot, dry and windy conditions meant the smallest spark could set off a fire.
He warned: "Climate change is increasing fire danger across the UK, and we need to be prepared for it."
Trackside fires and damage to overhead lines also halted train services, while there were widespread suspensions, disruptions, reduced services and temporary speed restrictions to cope with the risk of buckling rails.
Transport Secretary Grant Shapps conceded the UK's transport network cannot cope with the extreme heat, saying that the Victorian-era infrastructure "just wasn't built to withstand this type of temperature" and it would take decades.
Nine people have died or are feared dead in accidents in open water since Saturday, including several teenagers, and a swimmer who was missing at sea after an incident close to Clacton pier in Essex today.