Eight fire engines and around 60 firefighters tackled a fire on Kingsend in Ruislip.
Half of a walkway on the side of a supermarket was damaged by the fire. There were no reports of any injuries.
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.
The Brigade was called at 2226 and the fire was under control by 0010. Crews from Ruislip, Hillingdon, Harrow and surrounding fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.