Four fire engines and 21 firefighters and officers were called to a fire at a block of flats in Queensland Road in Islington.
A section of wall about four metres square in size on the second floor level was damaged by fire
Approximately 150 people were evacuated from the block of flats as a precaution.
The Brigade was called at 1941 and the fire was under control at 2119. Fire crews from stations including Holloway, Islington and Kentish Town fire stations attended the scene.
The cause of the fire is believed to be due to carelessly discarded smoking materials.