• June's heatwave in the UK led to 24 million lost hours of work and cost the economy £1.15 billion, with workers across the country forced to take time off or adjust their hours due to record-breaking temperatures.
• Physically demanding jobs in sectors like construction and agriculture saw workers reduce their hours more than those in low-exposure, undemanding jobs like academia, with 3.6% of respondents not working at all during the heatwave week, potentially resulting in an additional eight million lost hours at an estimated cost of £0.38 billion.
• 87% of respondents reported health-related impacts during the heatwave week, with women, those under 35, and individuals with existing health conditions most likely to experience harm, highlighting the need for the government to address workplace safety and adapt to the changing climate to prevent further impacts on productivity, health, and the economy.

June's heatwave led to 24 million lost hours of work and cost the United Kingdom economy £1.15 billion ($1.53 billion), research suggests.

Workers across the country were forced to take time off or adjust their hours during the week beginning June 22, which saw temperatures break the June record.

The heatwave marked the second of three to hit western Europe in just three months this year, causing escalating impacts on health, infrastructure, water resources, farming and wildlife.

The average reported reduction in hours worked across the last week of June in the UK was 0.47 hours, according to a survey analysis led by the London School of Economics' Grantham Research Institute on Climate Change and the Environment and the Euro-Mediterranean Centre on Climate Change (CMCC).

For the study published on Thursday, the researchers asked a nationally representative sample of 1,950 British adults about how the heatwave affected working hours, ability to sleep and any changes to their working routine during the week.

The team estimated the economic cost of lost output driven by the heatwave based on the workers' responses about adjustments they had to make.

They found that those working in physically demanding jobs that are more highly exposed to heat in sectors such as construction and agriculture reduced their hours by more than those working in low-exposure and physically undemanding jobs such as academia.

Findings from the survey also show 3.6% of respondents - equivalent to approximately 1.25 million workers in the population - did not work at all that week because of the heat.

This suggests there could have been an additional eight million lost hours - at an estimated cost to the economy of £0.38 billion.

Elsewhere, 87% of the respondents reported at least one health-related impact during the week, ranging from disrupted sleep and being more tired at work through to a small number of workers reporting more extreme symptoms including dizziness or fainting and a faster heartbeat.

The survey also found that 5% of respondents sought medical attention and around 3% reported an accident or injury at work during that week, with around two-thirds of them feeling it was linked to the weather.

Women, those aged under 35 and people with existing health conditions were the groups most likely to report that their health was harmed, the research found.

Elizabeth Robinson, director of the Grantham Research Institute, said: "Our findings point to a country that remains insufficiently adapted to the changing climate.

"The Government cannot continue to ignore extreme heat.

"Unless it acts now, and makes workplaces safer, we are likely to see growing impacts on workers' productivity, health, and the economy."

Shouro Dasgupta, environmental economist at the CMCC and visiting senior fellow at the Grantham Research Institute, said: "While £1 billion is lost overall, the greatest effects are borne by outdoor workers and those in physically demanding jobs, many of whom are among the lowest paid in the labour force.

"Extreme heat is widening existing inequalities in the labour force."