Eight fire engines and 58 firefighters and officers were called to a fire at a row of terraced houses in Marshall Path, Thamesmead.
The ground, first and second floors of one house were destroyed in the fire. The ground floor of the adjacent house was also destroyed in the blaze. Half of the first floor and part of the second floor were damaged by fire. A small part of another neighbouring house was damaged by fire.
Twelve people left the properties before the arrival of the Brigade and a local youth club opened to look after them. One man was treated at the scene by London Ambulance Service. One man and one woman presented themselves to hospital.
Three gas cylinders were involved in the fire. They were cooled and removed as some cylinders can explode when exposed to heat.
The Brigade was called at 1033 and the fire was under control at 1532. Fire crews from Plumstead, Erith, Bexley, and surrounding fire stations attended the scene.
The fire is accidental and believed to have been caused by a gas stove being used in the garden.