Ten fire engines and around 70 firefighters are tackling a fire on High Road, Wembley.
The fire has affected the ground floor, basement, ducting and second floor flat roof of two mid terraced shops with dwellings above.
Traffic is likely to remain impacted by the fire, so the public are advised to continue to avoid the area if they can.
One of the Brigade's 32-metre turntable ladders was used at the scene as a water tower to help fight the fire from above.
Control Officers took the first of ten calls at 1237 and mobilised crews from Wembley, Park Royal, Northolt and surrounding fire stations to the scene. The fire was under control by 1609.
The cause of the fire is under investigation.