Four fire engines and around 25 firefighters were called to a fire at a hotel on More London Place in Southwark.
Part of an electrical intake room in the basement of the building was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 1153 and the fire was under control by 1449. Fire crews from Lambeth, Homerton, Dockhead and Deptford fire stations were at the scene.
The Brigade's fire investigators believe the fire was caused by the failure of an electrical component in the distribution cupboard.