Four fire engines and around 25 firefighters tackled a fire at a flat above a range of shops and offices on Station Road in Harrow.
Part of a third-floor flat was damaged by fire. One man was assessed on scene for smoke inhalation.
The Brigade’s Control Officers took the first of six calls to the fire at 1523 and sent crews from Harrow, Stanmore, Northolt and Southall fire stations to the scene. The fire was under control by 1606.
The fire is believed to have been accidental and caused by an electrical malfunction in a desk fan.