Teachers in France are risking their own and students’ health in overheated schools as a severe heatwave sets new record temperatures, education unions said, urging staff to strike over “unacceptable working conditions”. Several teaching unions on Thursday issued a joint statement denouncing a “blatant lack of preparation” by the government, after teachers have had to work in classrooms where temperatures reached up to 40C.

The UK’s new provisional high of 36.4C (97.5F), recorded in Yeovilton, Somerset, surpassed Wednesday’s June record of 36.1C in Gosport, Hampshire, which had beaten the previous peak of 35.6C set in Southampton in 1976.

The Netherlands issued its first-ever red alert for heat for Friday, warning of “dangerous” conditions as a record-setting heatwave scorched Europe. The national weather institute issued the alert for much of the country, where temperatures are forecast to reach 40C in some places.

Switzerland registered its hottest ever June temperature on Thursday, with 38C measured in the northern city of Basel, breaking a previous record of 36.9C set eight decades ago, the Swiss weather service said. “Temperatures exceeded 37C for the first time in Switzerland during the month of June, breaking a record set in 1947,” MeteoSuisse said on X, adding that “a temperature of 38C was even recorded at the Basel weather station”.

France’s main energy provider Thursday shut down two nuclear reactors as an environmental protection measure to avoid discharging too much hot water into rivers already warming in a record-breaking heatwave, AFP reported. Power plants critical to the country’s electricity production use river water to cool their reactors, which heats the water that is then released back into the river.

In France, a three-year-old has died after finding himself trapped in a car in the Paris region in extreme heat, a prosecutor said, the third such fatality this week, AFP reported. The boy had slipped into the family car while his father thought he was napping, then found himself unable to get out with the child lock in the town of Saint-Gratien, the prosecutor said, after a police source and civil defence also reported the death.

A heatwave sweeping Europe was starting to peak in Germany on Thursday, with several open-air events cancelled and temperatures expected to top 40C through the weekend, AFP reported. Large parts of the country are already under “severe to extreme heat stress” with temperatures soaring to around 37C, the German Weather Service (DWD) said.

Italy’s latest heatwave has claimed five lives in less than 24 hours, as temperatures climbed to 41C across much of the country. After a 57-year-old man died while working in a field near Lodi, outside Milan, on Tuesday, four more deaths were reported on Wednesday.

Over the past four days 212 people have died prematurely in Spain as a result of the heatwave, according to scientists using a system for monitoring mortality. As temperatures rise to 42C in some regions, often not falling below 30C at night, the June heatwave is breaking records that were set this time last year, making it the hottest June since 1950.

In Germany, the country’s rail operator Deutsche Bahn, or DB, offered passengers booked for this weekend an option to cancel their ticket free of charge. The option is available to all passengers who booked their tickets before 23 June, and were due to travel between today and 30 June.

The heatwave continues to disrupt the British education system with University College London, one of the UK’s largest universities, cancelling its student open days planned for Friday and Saturday, relieving thousands of prospective undergraduates and parents from travelling to central London.