Sick and elderly patients have reportedly been left to suffer “sauna-like” conditions while being treated for life-threatening illnesses at the Royal Free after air conditioning units stopped working.

Patients in two wards at the hospital in Hampstead were said to have been left to “cook” as temperatures inside reach 27 degrees.

David Silver, 73, who is recovering after having his gall bladder removed, told the Daily Mail newspaper: “The air con first stopped working on Monday afternoon when it started getting really hot.

“It’s come on twice for a couple of hours in the night since but has stopped working again.

“It’s like being in a third world country up here. They’ve not offered us any fans and it’s about 80F (27C).

“People on this ward are really sick and vulnerable and many have just come from intensive care. We’re cooking up here – it’s just not acceptable for this to be happening.”

Due to a record-breaking heatwave hitting London yesterday, nurses shut the blinds and turned off the lights in the wards.

Sheena Downton, 58, who visited her daughter in the Royal Free with heart and liver problems, said: “The nurse came round and told us it had broken.

“My neck was soaking with sweat when I was up there in the ward with her, it was like being in a sauna.”

A spokesman for the Royal Free said: “On Tuesday the Royal Free Hospital experienced two localised air conditioning faults each covering around four beds which were repaired as soon as the fault was reported. At no point were patients put at risk.

“The Royal Free London is committed to the safety and comfort of its patients. Following the Met Office’s heat health alert on Monday, staff put in place a number of measures including identifying higher risk patients and moving them to designated “cool areas”, constantly monitoring indoor temperatures and closing blinds and curtains.”