Four fire engines and around 25 firefighters tackled a fire at a block of flats on Goldsmith Road in Peckham.
Part of a four roomed flat on the fifth floor was damaged by the fire. One woman left the building before the Brigade arrived. There were no reports of any injuries.
The fire is believed to have been accidental and was caused by a fault in an immersion heater.
Control Officers took the call at 2340 and mobilised four fire engines and around 25 firefighters to the scene from New Cross, Brixton, Deptford and Lambeth fire stations. The incident was over for firefighters at 0110.