Workers at a London hospital were unable to find a tap to hose down their overheating air conditioner as a critical outage saw dozens of appointments cancelled or delayed.

The bizarre admission was made in a review, published this week, into a critical incident that occured at Guy’s and St Thomas’ hospitals in July 2022 when two data centres failed during the UK’s record-breaking heatwave.

The review found the incident was likely preventable and said hospital management could have put in place measures to predict and mitigate the potential risks extreme weather now poses to its IT systems.

Despite the outage causing more than 100 delays to patients receiving care, only one person suffered “moderate harm” by being unable to receive an organ transplant. 

But climate campaigners said the report lays bare the UK’s lack of readiness for extreme weather caused by the climate crisis, and called on the government to invest more now to prepare.

In July 2022, both hospitals’ data centres failed when temperatures reached 40°C in London. It took six weeks before the system was fully restored and the response cost the hospitals £1.4m.

The review, which involved nine investigations, found that the ageing NHS estates are “vulnerable to failure” from extreme weather events and require “urgent” extensive infrastructure work to prepare it for future events. 

But the failure of the air conditioning system might have been averted altogether if earlier action had been taken to cool the data centre. A broken hose connector delayed attempts to water condensers at St Thomas’ while difficulties finding the water supply thwarted the response at Guy’s. 

“Following forecasts of the heatwave, preparations were put in place at the St Thomas’ data centre to manually hose down the condensers of the cooling system to keep down the temperature,” wrote the hospitals’ deputy chief exec. “This was carried out, but after a delay due to a broken hose connector.

“No such preparations were made at Guy’s hospital and, although manual cooling was attempted there on 19 July, it was also delayed by difficulty locating a water supply. Had preparations been made earlier, this delay could have been avoided.”

While the event caused no deaths or serious harm to patients it “took a heavy toll on staff, who reported fatigue, stress and an adverse impact on morale”, and were already exhausted by the pandemic.

“In particular, this affected frontline clinical and operational staff, who worked tirelessly to provide safe patient care, and also the IT team who worked tirelessly, often around the clock, to recover critical IT systems under immense pressure,” said the report.

NHS workers had to rely on using paper records for six weeks while they waited for the IT systems to be restored.

“It was a nightmare,” one hospital doctor told openDemocracy.

“They had to get a system of physical runners to run bits of paper around the hospital. It had a huge knock-on effect on things like doing a ward round, because you couldn’t see scans or blood results.”

NHS trusts warned last year that it “face[s] an uphill battle” to secure funding to improve its estates, and that competing demands on capital budgets presents a challenge to investing in energy efficiency.

Greenpeace UK’s head of climate justice, Kate Blagojevic, said: “This is a scary demonstration of how far reaching the devastating impacts the climate crisis go. 

“Extreme weather is pushing our infrastructure to the brink and the government must deliver a better plan and significant investment to make sure our buildings, systems and services are more resilient and better able to deal with the already baked-in consequences of rising temperatures.

“While effects are clearly being felt here in the UK, many developing countries are living with even more extreme climate impacts, paying the price for a crisis they did not create. The UK’s historic emissions and role in causing this climate chaos mean it has a responsibility to support those most in need. 

“The government should force polluters like the fossil fuel industry to pay for the damage they are causing and stop lives, homes and entire cultures from being washed away.”