Forty people have drowned in France over recent days as they sought to cool down to escape record heat, the prime minister said on Tuesday, as a heatwave swept across much of Europe.

Britain, Italy, Switzerland and Spain were also sweltering in extreme heat, with record temperatures in some areas disrupting schools and transport networks and forcing tourist sites – including the Eiffel Tower – to shut.

Europe is warming at more than twice the global average, according to the World Meteorological Organisation, making such prolonged heat episodes increasingly likely.

France experienced its hottest day on record on Tuesday, a Meteo France forecaster said, with a peak of 44.3 degrees Celsius (111.74 degrees Fahrenheit) in one town in the southwest.

Fifty-four departments are under red alerts in what Meteo France said was unprecedented. That will jump to 58 on Wednesday.    

Across the country, people have been jumping into canals and rivers to cool off. Sports minister Marina Ferrari said she understood the urge to escape the heat but warned against swimming in unauthorised or dangerous areas.