Four fire engines and around 25 firefighters tackled a fire in a residential building on Coral Row in Battersea.
Part of a single-storey generator room was damaged by fire. There were no reports of any injuries.
The Brigade was called at 1249 and the fire was under control by 1323. Fire crews from Battersea, Wandsworth, Chelsea and Fulham fire stations attended the scene.
The cause of the fire is under investigation.