At least three people have died as a heatwave likened to 'hell' swept across Europe , bringing with it temperatures of at least 40C.
The so-called Saharan Bubble weather is understood to have been linked to the deaths of three swimmers at beaches in France, according to local reports.
French news outlet LCI said the three swimmers had died in separate incidents on beaches in southern France.
A man aged 70 suffered a cardiac arrest in calm water and was believed to have been a victim of 'thermic shock' after coming into contact with the water.
Two other people died in similar circumstances. A woman, 62, died at a beach near Montpellier, and a man aged 75 also died at another beach nearby.
Parts of southern France and Spain recorded temperatures above 40 degrees.
French firefighters warned people should not swim in water that is too cold during the heatwave to avoid instances of so-called "hydrocution".
Swimmers are being advised to make sure they enter the water gradually.
European forecasters warned that “hell is coming” as the continent braces for the record breaking heatwave.
Meteorologists in France have issued warnings of a threat to life due to the heat and forecasters have predicted the country may experience its hottest June on record.
Parts of southern France and Spain recorded temperatures above 40 degrees on Wednesday.
The French weather agency set the heat warning level at orange - the second highest intensity on its four-level categorisation system for potentially dangerous conditions requiring public vigilance.
The alert system was introduced in France following the summer of 2003, which saw an estimated 15,000 heat-related deaths.
Many of those were older people left in city apartments and retirement homes that were not air-conditioned.
French authorities announced school closures and traffic restrictions due to the heat.
A 2,000 mile wide plume of hot air dubbed the “Saharan bubble” being blown across Africa is expected to bring hot conditions across the Continent to Britain following days of widespread downpours and flooding in the UK.
In Spain, forecaster Silvia Laplana tweeted a picture of an all-red weather map captioned: "El infierno [hell] is coming."
She later tweeted that while summer is hot, this "extensive and intense" heat was "not normal".
In Germany, temperatures above 40C are possible in some places on Wednesday, topping the country's previous June record of 38.2C, set in Frankfurt in 1947.
Parts of north-eastern Germany are also at high risk for forest fires. Authorities in the eastern state of Brandenburg, which circles Berlin, said the risk of forest fires is at the highest level in the coming days.
These graphics show how forecast temperatures for the next few days compare with average for the end of June. The areas which are expected to become hottest are slightly different from those forecast yesterday. The hottest day is now expected to be Saturday in eastern England pic.twitter.com/oLR4qqEraq— Met Office (@metoffice)June 25, 2019
French and German authorities also warned of water shortages, volunteers handed out bottled water to homeless people in Belgium and in Poland.
The transport ministry in Germany's eastern Saxony-Anhalt state said it has imposed speed limits of 62 mph or 75 mph on several short stretches of highway until further notice.
Poland also recorded its highest ever June temperature on Wednesday of 38.2 degrees Celsius - the use of fans helped drive power demand to a record high.
The UK’s Met Office said temperatures will become “increasingly warm over the next few days".
Temperatures are expected to climb as high as 31C this weekend.
Revellers heading to Glastonbury have been warned to take extra precautions such as sunscreen and to seek shelter from the sunshine due to high UV levels.
Forecasters also said there could be severe storms during the latter part of the festival, with thunderstorms and potential flooding.
Campers are due to be greeted by cloudy but dry weather when the gates open at 8am, with sunshine and temperatures of up to 23 degrees from mid-afternoon.
Chief Meteorologist, Steve Willington, said: “It’s going to get very warm across parts of the west and southwest of the country from Wednesday, and it’ll feel hot in places across southern and western parts of the UK by Friday, with temperatures possibly reaching 30 Celsius in a few spots.
“Localised heatwaves are possible in a few places across the UK by Saturday.”
The highest temperature on record for June is 35.6 Celsius recorded in London on 29 June 1957 and Southampton on 28 June 1976.
Scientists say measurements show that heatwaves in Europe are becoming more frequent.
Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research, said "monthly heat records all over the globe occur five times as often today as they would in a stable climate".