Four fire engines and around 25 firefighters were called to a maisonette fire on George Row in Bermondsey.
Part of a four-roomed, split-level maisonette on the fourth and fifth floors of the building was damaged by fire. One man left the building before the Brigade arrived and was taken to hospital by London Ambulance Service crews.
The Brigade was called at 1934 and the fire was under control by 2049. Fire crews from Dockhead, Old Kent Road, Deptford and Shadwell fire stations attended the scene.
The cause of the fire is believed to have been accidental and involved a gas torch.