London carries out disaster training exercise to test if it’s prepared for ‘unbelievable’ 40C heat

London carried out a training exercise to test its ability to cope with 40C heat on Thursday.

Named ‘Operation Helios’ after the Greek god of the sun, it explored a scenario where extreme heat hits the capital for five days - one scientists warn could be a reality as early as 2027.

It was led by Greater London Authority’s London Resilience Unit and involved more than 80 participants from emergency services to local government, environment agencies and transport companies.

It comes after the London Climate Resilience Review published a report in March which recommended that the city test its preparedness for a severe heat episode and identify potential risks.

Soaring temperatures can pose a threat to health, especially in vulnerable populations such as the very young or elderly. Extreme heat and dry weather can also trigger wildfires as they did in London in 2022. High temperatures are also often followed by heavy rain and flash flooding.

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“Recent summers have demonstrated that our climate is changing, which will affect all areas of our society, environment and economy,” David Bellamy, chair of the London Resilience Forum, said.

“Extreme heat and flooding poses real risks for Londoners, so as a partnership we need to prepare for weather conditions that previously would have been unbelievable.”

Bellamy added that exercises like Operation Helios help ensure we have the right tools and knowledge to handle emergencies and support Londoners through extreme weather events.

A new heat plan for a hotter London

The exercise looked at a developing scenario with updates and warnings from different agencies like the Met Office. Those taking part were advised to consider what impacts a period of extended heat could have on individuals, communities and services.

“We were inspired to make this recommendation when Paris ran an exercise that simulated a 10-day 50C heatwave in October 2023,” author of the report Emma Howard Boyd wrote on LinkedIn.

She added that the exercise would help to inform the development of another of the review’s recommendations, “a new pan-London Extreme Heat Plan”.

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Operation Helios came amid a four-day yellow heat warning issued by the UK Health Security Agency and the Met Office this week. Temperatures reached 30.3C at Heathrow Airport on Wednesday - the hottest it has been in the UK since September last year.

“Over the past few years we have seen the damaging and dangerous effects of extreme heat and climate change in London, and Operation Helios provides a vital opportunity to bring partners together and plan how we can manage these threats in the future,” Mayor of London Sadiq Khan said.