Four fire engines and around 20 firefighters and officers were called to a fire at a block of flats in Saint George Wharf, Vauxhall this morning.
Part of a flat on the third floor was damaged by fire.
Two people left the affected property and another 20 people left the block before the arrival of the Brigade.
Firefighters wearing breathing apparatus rescued a cat from the flat where the fire started.
The Brigade was called at 0254 and the fire was under control at 0357. Fire crews from Lambeth, Clapham and Brixton fire stations attended the scene.
The cause of the fire is under investigation.