Four fire engines and around 25 firefighters tackled a flat fire on Bensham Lane in Croydon.
Part of a first-floor flat in a converted semi-detached house was damaged by fire. There were no reports of any injuries.
The Brigade was called at 2053 and the fire was under control by 2216. Fire crews from Croydon, Norbury and Mitcham fire stations attended the scene.
The cause of the fire is believed to have been accidental.