Four fire engines and around 25 firefighters were called to a flat fire on Freelands Avenue in South Croydon.
Part of a four-roomed flat on the third floor of the building was damaged by fire. Three people left the property before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 1738 and the fire was under control by 1825. Fire crews from Addington, Croydon and Woodside fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.