Hospitals in England declare critical incidents as heat knocks out scanners and cooling systems

Several NHS trusts in England declared critical incidents on Thursday after extreme heat disrupted hospital infrastructure, including cooling systems, MRI scanners and IT equipment. The failures forced cancellations, reduced capacity and hit services that are difficult to replace at short notice.

The disruption has been most visible in Portsmouth and Norfolk, where trusts reported problems affecting diagnostics, theatres and other clinical services. At least 254 outpatient appointments were cancelled at Norfolk and Norwich University Hospitals, according to reported coverage.

The incidents add a new pressure point to the wider June heatwave, which has already strained public services across England. The failures show how quickly soaring temperatures can affect hospitals that rely on cooling systems, digital equipment and machine-intensive services.

What happened

Queen Alexandra Hospital in Portsmouth declared a critical incident after several chiller units failed in hot weather. Portsmouth Hospitals University NHS Trust said the problems affected digital systems and critical clinical services, including theatres, cardiac catheter laboratories and diagnostic scanning facilities.

Norfolk and Norwich University Hospitals NHS Foundation Trust also declared a critical incident after heat and humidity affected the cooling systems that support MRI scanners. The trust said it had no working MRI scanners across its Norwich sites at the time reported.

Reports also described overheating IT servers and other machine failures at affected hospitals. The result was a rapid loss of capacity in services that are hard to recover quickly, especially imaging and theatre support.

Impact on care

The immediate effect is on patients waiting for outpatient appointments, diagnostics and procedures. When scanners go down and cooling systems fail, trusts can be forced to cancel appointments and defer treatment to protect safety and keep essential services running.

The disruption also matters for cancer and other specialist pathways, where delays to imaging or theatre schedules can ripple through later stages of care. In a busy hospital system, even short outages can affect multiple departments at once.

The trust reports point to the same operational problem from different angles: cooling failures led to equipment failures, and equipment failures reduced the hospitals' ability to keep services open.

Wider heat pressure

The incidents come amid a severe UK heatwave that has already triggered a rare red heat warning and widespread disruption beyond hospitals. The research packet indicates this is part of a broader strain on public infrastructure, not an isolated technical fault.

The story also highlights the NHS's heat vulnerability. Older hospital estates, aging plant equipment and heavy dependence on digital systems can leave trusts exposed when temperatures rise sharply and cooling systems are pushed beyond capacity.

That makes the current disruption more than a single bad day for one or two hospitals. It is evidence of how climate stress can translate directly into lost clinical capacity.

What to watch

Trusts are likely to issue more updates on restoration timelines and any further cancellations. It is also worth watching whether other NHS trusts report similar failures or declare critical incidents for the same reason.

Questions remain over how many appointments or procedures have been lost across all affected hospitals, and how quickly MRI scanners, chiller units and IT systems can be brought fully back online.

National bodies including NHS England, the Department of Health and Social Care and UKHSA may also face pressure to respond to the disruption and assess what it says about heat resilience across the NHS.