Crews say they are responding to more people who are fainting, struggling to breathe and becoming unwell in the heat.
We’re being urged to only call 999 in a life-threatening emergency.
During the last heatwave in May, London Ambulance Service handled more than 8,000 calls to 999 in a single day.
A spokesperson for St George’s University Hospitals NHS Foundation Trust in Tooting said: “The extreme heat is putting extra pressure on our hospitals – our ageing buildings weren’t designed for these temperatures, but we are doing everything we can to keep people safe and comfortable, such as providing extra drinking water and prioritising air-con for our most vulnerable patients.
“People can also help us by staying safe in the heat, to avoid putting further demand on our emergency services.”
