Four fire engines and around 25 firefighters responded to a fire on High Street, Wealdstone.
The fire is located at a building consisting of commercial units with flats above. A single storey outbuilding was alight. The High Street was closed as crews responded.
The Brigade received the first of 17 calls reporting the fire at 1443, with crews from Harrow, Wembley and Mill Hill sent to the scene. Firefighters had the incident under control by 1626.