Researchers from Imperial College London, the Met Office and the London School of Hygiene & Tropical Medicine used historical mortality records and established peer-reviewed methods to model fatalities during both heat spikes. As Scotland and Northern Ireland were not impacted by such extreme temperatures, they focused on England and Wales.

Professor Lea Berrang Ford, Head of the UK Health Security Agency (UKHSA) Centre for Climate and Health Security (CCHS), said:

"These modelled estimates are based on past trends in temperature effects on mortality and provide an important indication of the potential health impacts of sustained hot weather, particularly for the most vulnerable among us. While they are not a measure of observed mortality, they help illustrate the scale of risk associated with extreme heat and the growing threat climate change poses to our wellbeing."