During 2022 – which saw the highest recorded temperature in England at 40.3C – there were an estimated 2,985 so-called “excess deaths” as a result of the heat, external, the most recorded in any given year.

There were an estimated 1,311 heat-associated deaths, external during summer 2024, and an estimated 1,504, external during summer 2025.

Most heat-related excess deaths are due to heart attacks and strokes caused by the strain of trying to keep body temperatures stable.

The higher death rate starts to kick in once the thermometer passes 25C-26C.

However, evidence suggests the deaths tend to be caused by higher temperatures in spring or early summer rather than during “peak summer”.

This could be because we start to change our day-to-day behaviour as summer progresses and we get more used to dealing with the heat.

The evidence from previous heatwaves is the increase in deaths happens very quickly – within the first 24 hours of a heatwave.