UK Health Security Agency figures for heat-related deaths that occurred in England in summer 2025

Responding to the publication today by the UK Health Security Agency of the figures for heat-related deaths that occurred in England in summer 2025, Emma Howard Boyd, Professor in Practice and Chair of the National Heat Risk Commission at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, said:

“The mortality figures published today (1504 heat-associated deaths observed during 5 heat episodes, with London and the East of England experiencing the highest number of heat-associated deaths over the summer – 317 and 323 respectively) confirm our fears: the five heat episodes over the summer of 2025 claimed hundreds of lives across England. With a significant number of lives lost in the capital – we are seeing the devastating ‘urban heat island’ effect in its most literal and tragic form.

“These are not just statistics; they are a failure of our built environment to protect the most vulnerable. It is why the Mayor of London’s upcoming launch of the London Heat Delivery Plan is so vital. This plan, a direct response to the recommendations of the London Climate Resilience Review, must be the blueprint we need to stop our homes and streets from becoming death traps.

“These figures are a sobering reminder that extreme heat is not an equal-opportunity killer. It disproportionately claims the lives of the most vulnerable – the elderly in care homes and in hospitals, and people with underlying health conditions. But they also highlight the importance of early season planning and preparedness across the health and care sector, which may have helped reduce the overall number of deaths.

“As Chair of the National Heat Risk Commission, I am clear: we can no longer rely on emergency ‘sticking plasters.’ We need the kind of systemic, long-term resilience that London is now pioneering to be rolled out across the entire country. Adapting to heat is no longer an optional policy goal; it is a matter of national survival.”

Bob Ward, Chair of the London Climate Ready Partnership and Policy and Communications Director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, said:

“We should welcome the lower than expected number of deaths in London and across England during our warmest summer on record. However, this was still a devastating natural disaster with many preventable deaths. If 1504 people had been killed by a flood the nation would rightly regard it as a national tragedy, and we should not treat these deaths any less seriously.

“The lower than expected mortality may be a sign that we are becoming better at protecting those who are most vulnerable to heat. However, the lack of clarity about why the deaths were lower is symptomatic of a country that still does not take this issue seriously enough. We have established the National Heat Risk Commission to identify how to make our preparedness a priority for the country so that we reduce the impacts on lives and livelihoods from rising temperatures driven by climate change.”