Four fire engines and around 25 firefighters tackled a fire at a residential block of flats on Warham Road in Croydon.
Half of a four-roomed flat, on the second floor of the three-storey building, was destroyed by fire. Two adults left the property before the Brigade arrived, one of whom suffered superficial burns.
The Brigade was called at 1419 and the fire was under control by 1534. Crews from Tooting, Norbury, Woodside and Addington fire stations attended the scene.
The cause of the fire is under investigation.