Four fire engines and around 25 firefighters were called to a flat fire on Purley Oaks Road in South Croydon.
Part of a five-roomed flat on the first floor of a converted semi-detached house was damaged by fire and a small part of a flat on the ground floor was also damaged by the blaze. One man was taken to hospital by London Ambulance Service crews after suffering from smoke inhalation.
The fire is believed to have been caused by the failure of lithium-ion batteries.
A London Fire Brigade spokesperson said: “Batteries can present a fire risk if they’re over-charged, short circuited, submerged in water or damaged, so it’s really important to protect them against being damaged and charge them safely.
"Unplug devices once they have finished charging and always make sure you use the right charger for your device.”
The Brigade was called at 0250 and the fire was under control by 0419. Fire crews from Croydon, Purley, Woodside and Wallington fire stations attended the scene.