Four fire engines and around 25 firefighters tackled a flat fire on Mount Ephraim Road in Streatham Hill.
Part of a five-roomed flat on the lower ground floor of a residential block was damaged by fire. Part of three further flats on the ground, first and second floors of the building were also damaged by the blaze and an external patio to the rear of the property was destroyed. There were no reports of any injuries.
The Brigade’s 999 Control Officers took 17 calls to the blaze.
The fire is believed to have been accidental and caused by the unsafe disposal of smoking materials.
A London Fire Brigade spokesperson said: “We’d rather you didn’t smoke at all, but if you are a smoker, it’s absolutely vital you ensure your cigarette is completely out when you’ve finished smoking it.
“If you don’t, you risk causing a fire which could not only destroy your home, but also cost you your life.”
The Brigade was called at 2201 and the fire was under control by 2321. Fire crews from Norbury, Tooting and West Norwood fire stations attended the scene.