(BBC) The UK hit its highest ever temperature of 40.2C, according to provisional Met Office figures, and forecasters warned temperatures were still climbing.
Extreme heat warnings were issued in France while northern Spain saw temperatures of 43C (109F) on Monday.
Deadly wildfires in France, Portugal, Spain and Greece have forced thousands of people to evacuate their homes.
Two people were killed by forest fires in Spain’s north-western Zamora region and trains in the area were halted because of fire near the tracks. An elderly couple died while trying to escape fires in northern Portugal.
Several parts of France saw their hottest-ever days with the western city of Nantes recording 42C, the national weather office said.
Wildfires in recent days forced more than 30,000 people to flee, with emergency shelters set up for evacuees. A zoo with 1,000 animals was among the areas evacuated.
Gironde, a popular tourist region in the south-west, has been hit particularly badly, with firefighters from across France battling to control two blazes that have destroyed 19,300 hectares (47,700 acres) of land in the past week. The city of Bordeaux was blanketed by smoke early on Tuesday as the wind changed direction.
“The idea that comes into my head is, it’s a monster,” said Jean-Luc Gleyze, Gironde’s regional president.