Doctors have detailed the severe impact of extreme heat on the NHS in England, with radiotherapy machines and MRI scanners failing, critical IT systems stalling, and cooling units that serve entire hospitals breaking down. The hot weather has also prompted a surge in admissions and people arriving at A&E, causing severe overcrowding and exacerbating heat-related pressures on infrastructure.
Overcrowded wards and failing equipment
“Lots of people, especially older patients, are turning up having collapsed or with dehydration,” one physician said. “In terms of inpatients, the conditions are awful due to overcrowding. Very few places have air conditioning and staff are really struggling.” Older patients in one geriatric ward had been forced to endure temperatures as high as 35C, a second doctor said. Even wards with built-in air conditioning were affected, as some units were shut down to prevent damage from the extreme heat.
Another doctor described their workplace as “unfit to cope,” with patients and staff experiencing “awful conditions” in sweltering wards, clinics, and corridors. NHS staff were also navigating the challenge of providing care while sleep-deprived, as many struggled to sleep during the heatwave. Some medics were unable to work because their children’s schools had closed.
Critical incidents declared across England
Several NHS trusts in England have declared critical incidents as a direct result of the extreme heat. One hospital did so after its machines failed in multiple areas, a doctor said. Labs used for testing were affected, and two linear accelerator machines used to treat cancer patients stopped working amid the high temperatures. The doctor noted that while they were working in a relatively new care setting, it was “tacked on to an old Victorian hospital,” creating severe infrastructure challenges. “It’s hopeless, really,” they said.
The same doctor also reported that their NHS trust faced “major issues” with IT servers overheating on Wednesday. “We thought we were going to lose everything, so we were all asked to turn off non-essential computers and electrical equipment, including lights.”
Queen Alexandra hospital and Norfolk MRI failures
In Portsmouth, Queen Alexandra hospital declared a critical incident after extreme heat caused cooling units to fail, leading to “elevated temperatures” across the hospital. Portsmouth hospitals university NHS trust said the failure affected digital systems and critical clinical services, including operating theatres, cardiac catheter laboratories, and diagnostic scanning facilities. “The unprecedented pressures created by the current heatwave, combined with the failure of a number of our chiller units, have led to significant disruption across several of our services,” said deputy chief executive Mark Orchard. Some planned care and appointments were cancelled, and patients attending appointments were advised to bring plenty of water as the hospital was “very hot.”
In Norfolk, hundreds of patients had hospital appointments cancelled after MRI scanners stopped working in the extreme heat. Norfolk and Norwich university hospitals NHS foundation trust declared a critical incident, saying cooling systems that kept its scanners running had been affected by the hot weather and humidity. It stated it currently had “no working MRI scanners” across its Norwich sites, including its main hospital and community diagnostic centre.
Record emergency calls and expert warnings
London Ambulance Service reported the highest number of life-threatening emergencies in its history in a single day, “driven by the extreme heat.” Ambulance crews responded to a record 642 category one calls on Wednesday, which include the most serious, life-threatening injuries and illnesses such as cardiac arrests and patients who are not breathing.
Dr Hilary Williams, clinical vice-president of the Royal College of Physicians, said the impact on patients and staff exposed an NHS that was dangerously underprepared for this week’s extreme heat. “There are reports of older patients arriving at hospital having collapsed or with dehydration. Patients are facing overcrowding, and there are issues with machines, laboratories and kidney dialysis – all fundamental to providing safe patient care,” she said. “The impact of heatwaves on staff cannot be overstated. There is a sense of foreboding when we see the weather forecast, because we know what is to come, and there is very little staff can do.”
Williams added that buying fans is not a simple solution, as they can present a fire risk when used alongside oxygen and may increase the spread of infection. She stressed that the NHS was already under “enormous pressure” due to rising demand and workforce shortages, and that record temperatures intensified these challenges. “As clinicians, there are immediate steps we can take to protect patients, such as reviewing medications that affect hydration and ensuring they are stored appropriately,” she said. “But this must be matched by system-level change – strengthening infrastructure and embedding resilience into NHS reform.”
Williams called for buildings to be upgraded to withstand extreme heat and other climate risks. “Hospitals should be places of safety, not settings where extreme heat puts patients and staff at risk.”
The Department of Health and Social Care said all NHS trusts were required to have effective arrangements to deal with extreme heat. “Trusts are urgently coordinating responses to increased demand on health services and protecting vulnerable patients,” a spokesperson said.
