Ten fire engines and around 70 firefighters were called to a fire at a flat in Lewisham Road in Lewisham.
A five-roomed flat on the third floor of the four-storey block was destroyed by the fire and part of the roof was damaged. Around 40 people left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 1635 and the fire was under control at 1820. Fire crews from East Greenwich, West Norwood, Greenwich, New Cross, Peckham, Lewisham, Old Kent Road and surrounding fire stations attended the scene.
The cause of the fire is under investigation.