Five fire engines and 31 firefighters and officers were called to a fire in a block of flats under construction in Blackfriars Road, Southwark.
A small part of a wall void between the second and third floor of the nine-story block was damaged by fire.
The Brigade was called at 0117 and the fire was under control at 0530. Fire crews from Lambeth, Dowgate, Dockhead and Old Kent Road fire stations attended the scene.
The cause of the fire is under investigation.