Four fire engines and around 25 firefighters were called to a fire at a flat on Brighton Road in Sutton.
Part of a flat on the second floor of the three-storey block was damaged by the fire. Twelve people left the building before the Brigade arrived. One man was taken to hospital as a precaution by London Ambulance Service crews.
The Brigade was called at 2137 and the fire was under control by 2245. Fire crews from Sutton and Wallington fire stations were at the scene.
The fire is believed to be accidental and caused by combustible items coming into contact with a hot plate, causing them to ignite.