Temperature reached 35°C near London and could hit 39°C in some areas of France.
The heatwave affecting France and a large part of Europe is "completely unprecendented and historic", weather forecaster at Météo-France Adrien Warnan said.
Temperature reached 35°C near London and could hit 39°C in some areas of France.
The British are facing the warmest May on record.
"Well, I'm working in the kitchen, so it's atrocious," Renata Stankeviciute, a Lithuanian chef living in England, says.
In Paris, tourists adapt their visit amid an unprecedented heatwave.
"In the first part of the day, everything is going well and interesting. But then I'm going to my flat and just sleep because I need to have more energy, because it's so, so hot in this time," Sabina Ismailova, a 29-year-old tourist from Ukraine says.
Around 1 500 people died because of the heat in England last summer, Britain's health security authority said.
The Policy and Communications Director at LSE's Grantham Research Institute on Climate Change and the Environment says Britain will have to make changes to homes and businesses to make them less dangerous.
"We know that the temperatures we reached yesterday, which were nearly 35 degrees in London, unfortunately will likely have killed hundreds of people across the country, people with underlying health conditions, particularly respiratory illness. And they mainly die in homes that overheat."
The current heatwave is not an emergency, the French health minister Stéphanie Rist said, though she urged the public to be cautious and follow safety guidelines.