London is bracing for a week-long heatwave with temperatures forecast to reach 40C on Wednesday, triggering a red extreme heat warning from the Met Office. Tuesday will see highs of 36C, while the rest of the week will remain between 27C and 29C.
Many Londoners face sweltering conditions in offices and on public transport, particularly the Tube, which lacks adequate cooling. The Workplace (Health, Safety and Welfare) Regulations 1992 require employers to provide a 'reasonable' temperature and good ventilation, but there is no legally binding maximum or minimum temperature for workplaces.
What Does the Law Say?
The Approved Code of Practice recommends a minimum of 16°C (or 13°C for physical work), but no equivalent guidance exists for high temperatures. The Health and Safety Executive (HSE) states that 'in such environments, it is possible to work safely provided appropriate controls are present.'
The Chartered Institute of Building Service Engineers recommends: heavy work in factories at 13°C, light work in factories at 16°C, hospital wards and shops at 18°C, and offices and dining rooms at 20°C.
Employee Rights During Hot Weather
According to the Government website, 'Employees should talk to their employer if the workplace temperature is not comfortable.' The HSE advises that if a significant number of employees complain about thermal discomfort, employers should carry out a risk assessment and act on the results. Employers must also ensure access to water.
However, discomfort does not automatically entitle workers to leave. In June 2024, the Trades Union Congress called for a legal maximum working temperature, warning that heat can cause dehydration, rashes, fainting, and loss of consciousness, and that outdoor workers are three times more likely to develop skin cancer.
International Comparisons
In Spain, a work limit applies if office temperatures exceed 27°C, and many businesses close for August. France and Germany lack a defined upper limit but have strict workplace protections. The HSE notes that acceptable thermal comfort for most people lies between 13°C and 30°C.
Currently, there are no official UK plans to introduce a statutory maximum working temperature.
