Five fire engines and around 35 firefighters were called to a fire at a sheltered accommodation block on Endsleigh Gardens in Bloomsbury.
Half of a flat on the fourth floor of the building was damaged by fire. There were no reports of any injuries.
Station Commander Chris Young, who was at the scene, said: “On arrival, crews could see light smoke coming from a fourth floor window and worked quickly to bring the fire under control.
“One person left the affected flat before the Brigade arrived and around 30 people were evacuated by on site staff."
The Brigade was called at 1049 and the fire was under control by 1152. Fire crews from Euston, Soho, Paddington and Islington fire stations attended the scene.
The Brigade's Fire Investigators believe the fire was accidental and caused by a match which broke off whilst being struck and came into contact with clothing.