Met Office Issues Red Warning as Forecast Highs Reach 40C in Parts of England and Wales

The Met Office has issued a rare red warning for extreme heat covering central, southern and south-east England and parts of south Wales. The alert begins at 09:00 on Wednesday and runs until 21:00 on Thursday, with temperatures forecast to reach 40C in places during that period. Several schools in the affected areas have announced they will close early or entirely during the peak heat.

No legal maximum temperature exists for UK classrooms, and the government does not normally advise closures. Teaching unions recommend keeping indoor temperatures at or below 26C. Head teachers who decide to close must first consult the chair of governors and their academy trust or employer.

The Department of Health and Social Care advises against vigorous physical activity for children in very hot conditions. UK Health Security Agency guidance states that windows may need to be closed later in the day if outdoor temperatures exceed indoor ones and that fans should not be used above 35C. No UK law sets a specific temperature threshold as too hot or too cold for work.

Health and Safety Executive rules require employers to maintain comfortable workplace temperatures and provide clean fresh air. In cold weather the minimum indoor workplace temperature is normally 16C, or 13C for rigorous physical work. Last month the Climate Change Committee called for a legal maximum workplace temperature.

National Highways recommends drivers carry ample drinking water for all passengers. The RAC advises owners of vehicles without effective air conditioning to postpone non-essential journeys until the warnings end. Hot weather can affect railway overhead power lines and cause rails to buckle, potentially disrupting services.