The UK has broken its all-time temperature record for June, as the World Health Organization chief says Europe’s heatwave is “putting lives at risk”.

Temperatures bolstered by climate breakdown hit 35.7 in southern England, according to provisional records reported by the BBC. The record high was reached in Charlwood, Surrey.

The previous June record of 35.6C was set in Camden Square in London in 1957 and was reached again in Southampton in 1976. The highest temperature ever recorded in the UK is 40.3C, reached on 19 July 2022 at Coningsby in Lincolnshire.

The Met Office issued a rare red extreme heat warning for 9am on Wednesday until 9pm on Thursday. Further amber warnings are in place for Friday and Saturday.

Schools, hospitals, care homes and workplaces have struggled to handle sweltering temperatures that stress organs and push people beyond what their bodies can handle. Coping measures this week have resulted in trains driving slower, hospitals cancelling appointments, schools closing early or completely, and hosepipe bans.

Matthew Lehnert, the Met Office chief forecaster, said on Wednesday the heat was “exceptional” for June. “High humidity is an additional factor for this heatwave, which will mean the heat will feel much more potent for many,” he said.

Heatwaves kill tens of thousands of people across Europe each year and the most scorching extremes have grown hotter, longer and more common as the planet has warmed. Climate breakdown is thought to have increased temperatures by 2C to 4C, according to a rapid analysis published by ClimaMeter on Monday.

Tedros Adhanom Ghebreyesus, the director general of the WHO, said Europe’s heatwave was “putting lives at risk” on Wednesday. He urged world leaders to invest more in resilient health systems and act faster on climate change.

“The data are clear: temperatures across Europe are rising at roughly twice the global average rate, increasing the likelihood and severity of extreme heat in the future,” he said. “We cannot afford further delay.”

France, which recorded 40 deaths from drowning as people sought to escape the heat, experienced its hottest night on record on Monday, followed by its hottest day on record on Tuesday, according to averaged temperature data from the country’s national weather service Météo-France.

In Spain, one in every eight weather stations recorded temperatures above 40C on Monday. Temperatures are slightly cooler in central Europe but are creeping higher, with Germany expected to hit 40C at the weekend.

Caroline Abrahams, the charity director at Age UK, said: “Red extreme heat weather warnings are rare so when the Met Office issues one we need to take it seriously, especially if you are an older person living with underlying health conditions like heart or lung problems that increase your risk of heat-related harm.”

She urged vulnerable people to take extra care over the next few days and called on the public at large to look out for older people around them.

“There are lots of simple precautions that older people can take to stay safe, such as keeping in the shade, drinking plenty of water and confining activities like walking or shopping to early or late in the day, certainly outside the hottest hours between 11am and 3pm,” Abrahams said.

“Keeping your home as cool as possible by closing curtains and windows during the day and opening them at night will make a difference, too.”