The Met office expects "population-wide adverse health effects, not limited to those most vulnerable to extreme heat, leading to serious illness or danger to life."
"Exceptional, perhaps record-breaking, temperatures are likely on Monday, then again on Tuesday," it added, recalling that the highest temperature recorded in the UK so far was 38.7 degrees Celsius at Cambridge Botanic Garden in July 2019.
Similar precautions were raised by the Irish Meteorological Office (Met Éireann), which issued an orange heat alert for this weekend and the beginning of the next. It expects temperatures to be between 25 and 32 degrees Celsius during the day and between 15 and 20 degrees Celsius at night.
The anatomy of our looming heatwave...
The cut-off low spinning to the west of Portugal is helping intensify the heat over Moroccos & Iberia as we speak. This feature will essentially act like Europe's heat pump. pic.twitter.com/HgqOb7rlwm
Meanwhile, the heatwave left over 300 dead and fires in southern Europe. From July 10 to 12, at least 84 people died in Spain, where cities like Madrid, Seville, Zamora, and Ourense recorded temperatures of 40 degrees Celsius.
The situation is even worse in Portugal, where a temperature of 47 degrees was recorded on Tuesday. Between July 7 and 13, the Health Directorate recorded an "excess mortality" of 238 deaths over the usual average. Dehydration, decompensation, or chronic diseases are some of the factors that can suddenly worsen the health of some people to the point of death.
In the Mediterranean, the most visible consequence of the heat wave is the fires. French authorities reported three uncontrolled fires, the worst of which are in the Gironde department, where 7,500 hectares have already burned and over 11,300 people have been evacuated.