- Temperatures could reach 40°C in parts of England and Wales.
- More than 850 schools have closed or shortened the school day.
- Rail operators and energy officials have warned of major disruption.
A rare UK red heat warning has triggered widespread disruption across Britain, with schools closing, rail services being scaled back and authorities urging people to avoid unnecessary travel as temperatures edge towards record levels.
The UK heatwave is expected to bring temperatures of up to 40°C across parts of England and Wales on June 25 and June 26, putting the country on course for one of its hottest June periods on record. Forecasters say the current spell of extreme weather could surpass the previous June record of 35.6°C, set in Hampshire in 1976, and come close to the UK's all-time high of 40.3°C recorded in Lincolnshire in July 2022.
The conditions are being driven by a "heat dome" over western Europe, trapping hot air across large parts of the continent and pushing temperatures well above seasonal norms.
Schools shut as heat emergency unfolds
The impact is already being felt across education systems in England and Wales.
More than 850 schools have either closed completely or shortened their operating hours, while some have relaxed uniform rules and allowed pupils to attend in PE kits to help them cope with the heat.
Wales has been particularly affected, with more than 500 schools closing ahead of the red warning. Several local authorities, including Blaenau Gwent, Caerphilly and Bridgend, announced large-scale closures to protect pupils and staff.
Nerys Evans, Wales' Deputy Minister for Public and Preventative Health, reportedly described the situation as a "heat emergency" and urged people to stay hydrated, avoid prolonged exposure to the sun and check on vulnerable neighbours and relatives.
Railways slow down, power system under pressure
Transport operators have also moved to reduce services as soaring temperatures increase the risk of infrastructure failures.
Chiltern Railways has cut more than half of its services until June 27, affecting routes between London Marylebone and destinations including Birmingham, Oxford and Aylesbury.
Great Western Railway has urged passengers to travel only if necessary, warning that speed restrictions and operational changes will result in fewer services and longer journey times. Network Rail has also limited the movement of some track-switching equipment to reduce the risk of heat-related failures.
LNER reportedly advised customers against travelling on June 25 and June 26, while operators including Avanti West Coast, Great Northern, Southern and Thameslink warned of cancellations and delays.
The heat has also reached Buckingham Palace. The Army cancelled ceremonial duties, including the Changing of the Guard in London and Windsor, citing concerns over the wellbeing of personnel.
Meanwhile, Britain's electricity system is coming under growing strain. The National Energy System Operator (NESO) has issued an Electricity Margin Notice, a relatively rare measure used when additional generating capacity may be needed to meet demand.
The notice does not mean blackouts are expected, but it signals concerns that electricity supplies could come under pressure as homes and businesses increase energy use during the heatwave.
The AA also reported that vehicle breakdown callouts were becoming more difficult to manage due to the extreme temperatures.
With the red warning remaining in place and temperatures expected to stay exceptionally high, Britain faces several days of disruption as transport operators, schools and public services attempt to adapt to conditions more commonly associated with southern Europe than the UK.
