Four fire engines and around 25 firefighters were called to a fire at a house on Green Lane in Morden.
Part of the first floor of a terraced house was damaged by fire. Three people left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 1133 and the fire was under control by 1228. Fire crews from Sutton, Mitcham and Wimbledon fire stations attended the scene.
The fire is believed to be accidental.