Six fire engines and 35 firefighters and officers were called to a fire at a block flats above a shop in Mount Street in Mayfair.
Part of a third floor flat and part of the flat roof at third floor level were damaged by fire.
The Brigade was called at 0810 and the fire was under control at 0946. Fire crews from Soho, Euston, Paddington and Chelsea fire stations attended the scene.
The cause of the fire is believed to be accidental and due to a fault within a consumer unit.