Four fire engines and around 25 firefighters were called to a fire at a house on Hamilton Terrace in St John’s Wood.
Part of the second and third floors of a terraced house were damaged by fire. There were no reports of any injuries.
The Brigade’s 999 Control Officers took 13 calls to the blaze.
The Brigade was called at 1925 and the fire was under control by 2032. Fire crews from West Hampstead and Kentish Town fire stations attended the scene.
The Brigade’s Fire Investigators believe the fire was accidental and involved a sauna.