Fifteen fire engines and around 100 firefighters were called to a fire at a house on Vicarage Gate in Kensington.
Part of the second, third and fourth floors of a five-storey house were alight.
Station Commander Jon Singleton, who was at the scene, said: “On arrival, crews were faced with smoke coming from the house and upon investigation located the fire inside a wall void.
“Due to the complex location of the fire, crews used specialist cutting equipment to gain access. Crews worked to prevent the fire from spreading to adjacent properties.
“A turntable ladder was used to provide a bird’s eye view and monitor the incident.
“Roads in the local area were closed whilst firefighters work to make the scene safe.”
The Brigade was called at 12.54pm and the fire was under control by 9.33pm Fire crews from Kensington, Hammersmith, North Kensington, Paddington and surrounding fire stations were at the scene.
The cause of the fire is under investigation.