Climate change could send heatwave temperatures in the South-East of England soaring as high as 46C (114.8F) by the end of the century, the Met Office has warned.
Simulations based on a range of possible increases in carbon dioxide emissions show peak temperatures across Europe rising as a whole between 4C and 10C above their current highs by 2100.
The research also points to stifling hot spells becoming an almost annual event, and the possibility of a 20-fold increase in the number of days with extreme temperatures.
In Britain, where severe heatwaves such as that of July 2006 are currently seen once every 20 years, such hot spells would become common, the Met Office said. "By 2100, such heatwaves are likely almost every year, and could even occur several times in any given summer," it said.
Global temperatures are expected to rise by between 2C and 5C above current levels by the end of the century. The range depends on how much greenhouse gas emissions rise by in that period.
With carbon dioxide levels currently at around 385 parts per million of air, a rise of 2C would equate to levels of 450ppm. But without quick action, the Met Office said levels could hit 800ppm, sending temperatures up 5C.Reuse content