More than 2,700 people may have died in exceptional May and June heatwaves in England and Wales

More than 2,700 people may have died as a result of the exceptional heatwaves that struck England and Wales in May and June, according to new estimates that make the period one of the deadliest extreme weather events in modern British history.

The figures, produced by the Office for National Statistics using the standard methodology for estimating excess mortality, represent the highest heat-related death toll since the 2022 heatwave, which killed approximately 3,200 people. The ONS cautioned that the figures are preliminary and subject to revision as more complete death registration data becomes available.

The deaths were heavily concentrated among people aged 75 and older, who accounted for more than 80 percent of the excess mortality. People with pre-existing cardiovascular and respiratory conditions were also disproportionately affected, as were residents of urban areas where night-time temperatures remained above 20°C for extended periods, denying the body the recovery window it needs to cope with daytime heat.

The geographical distribution of the deaths is striking. London recorded the highest mortality rate, with approximately 28 excess deaths per 100,000 population during the heatwave periods. The West Midlands, the East of England and the South East also recorded significantly elevated mortality. The North of England and Scotland, where temperatures were lower, saw little or no excess mortality attributable to heat.

Public health experts say the death toll should be understood as preventable. Countries that have invested in heat adaptation — including public cooling centres, urban greening, building standards that prioritise cooling as well as heating, and public information campaigns — have significantly lower heat-related mortality than countries that treat heatwaves as exceptional events rather than predictable consequences of a warming climate.