Three UK hospitals declare critical incidents amid heatwave

Three NHS hospitals have declared critical incidents after extreme heat and humidity disrupted cooling systems, scanners and digital services during the UK heatwave.

The affected sites are Queen Alexandra Hospital in Portsmouth, the Royal Devon and Exeter Hospital, and Norfolk and Norwich University Hospitals NHS Foundation Trust. The disruption forced service changes, cancelled appointments and left some key equipment unavailable at times.

At Queen Alexandra Hospital, Portsmouth Hospitals University NHS Trust said cooling-unit failures affected digital systems and critical clinical services, including operating theatres, cardiac catheter laboratories and diagnostic scanning facilities. The trust declared a critical incident while staff tried to keep services running safely.

The Royal Devon and Exeter Hospital also declared a critical incident because of the widespread impact of extreme heat and humidity on its ability to deliver services. Norfolk and Norwich University Hospitals said its MRI scanners were affected by cooling-system problems, and reported that it had no working MRI scanners across its Norwich sites at the time reported.

How the disruption unfolded

The reports emerged on June 25, when The Guardian said several NHS hospitals had declared critical incidents as machines and IT failed in the heat. A follow-up Guardian report the same day quoted doctors describing overheating wards, dehydration, corridor care and infection-control problems as temperatures climbed.

By June 26, later coverage named the three hospitals most clearly linked to the disruption and said the incident had already forced hundreds of appointment cancellations. The reporting said at least 362 outpatient appointments were cancelled across the affected sites.

The main operational problem was not just discomfort for patients and staff. The heat was affecting the infrastructure hospitals rely on to deliver routine and urgent care, including cooling units, IT systems and imaging equipment.

At Queen Alexandra Hospital, the cooling failures were said to have hit digital systems as well as theatres, catheter labs and scanning. At Norfolk and Norwich, the immediate issue was the loss of MRI capacity because the scanners could not be kept within safe operating conditions.

The Royal Devon and Exeter Hospital’s declaration reflected a broader loss of service capacity caused by the heat and humidity. The reports do not yet set out a full timeline for recovery at each trust.

Wider pressure on the NHS

The heatwave has also been hitting emergency care beyond the three hospitals. The London Ambulance Service recorded 642 category-one calls in a single day, described in the reporting as its highest number of life-threatening emergencies on record.

Doctors quoted in coverage said the heat is amplifying long-standing strains in the NHS, with unsafe ward conditions, dehydration, overcrowding and equipment failures all becoming harder to manage as temperatures rise. The effect is especially concerning for frail and older patients.

NHS England said local organisations were working to keep staff and patients safe by managing temperatures, supporting hydration and prioritising higher-risk patients. The Department of Health and Social Care said NHS trusts are expected to have effective arrangements in place to deal with extreme heat.

The episode comes during a rare red extreme-heat warning in the UK and has exposed how vulnerable parts of the hospital estate remain to cooling failures. It also adds pressure to outpatient, diagnostic and planned-treatment lists at a time when services are already stretched.

Further cancellations or service changes remain possible if temperatures stay high or equipment cannot be restored safely. The scale and duration of the disruption at each trust remain unclear.