The hospital’s chief operating officer, Chris Cobb, said: “The operational teams are reaching out to other healthcare providers for help, and our estates teams are working towards a cooling resolution; however, this situation may not be resolvable in the short term, particularly while the hot weather lasts.
“We would like to apologise to everyone affected by this incident.”
Cobb said staff were working “tirelessly to find a resolution”.
If patients have not been contacted, they have been advised to attend appointments as normal.
The disruption comes as other hospitals reported similar problems during the heatwave.
Queen Alexandra Hospital in Portsmouth, external also declared a critical incident after several of its chiller units failed, leading to increased temperatures across parts of the hospital and affecting services including scanning and IT.
The incidents underline the pressure extreme heat can place on hospital infrastructure, with cooling system failures at both sites linked to the high temperatures.
Some experts have warned that many NHS buildings are not well-adapted to cope with prolonged heat.
A report published in 2025, external by the UK Health Alliance on Climate Change found that 90% of hospital buildings were vulnerable to overheating.
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