Six fire engines and around 40 firefighters were called to a fire at a flat on Broadley Street in Marylebone.
A flat on the fifth floor was destroyed by fire. There were no reports of any injuries.
The Brigade was called at 1537 and the fire was under control at 1656. Fire crews from Paddington, Kensington, Lambeth, and North Kensington fire stations attended the scene.
The cause of the fire is under investigation.