Four fire engines and around 25 firefighters were called to a fire in a garage below a block of flats on Baldry Gardens in Streatham.
An internal, ground-floor garage and a car were destroyed by fire. Seven women, a man and five children were treated on scene by London Ambulance Service crews and seven of them were taken to hospital.
The Brigade’s 999 Control Officers took 20 calls to the fire.
Station Officer Simon Cook, who was at the scene, said: “We arrived to find a car fully alight in a car port underneath a block of flats. The blaze was producing a large amount of smoke in the area.
“Crews worked quickly to bring the fire under control and assisted local residents.”
The Brigade was called at 0327 and the fire was under control by 0446. Fire crews from Norbury and West Norwood fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.