Six fire engines and around 40 firefighters tackled a fire in an industrial unit on Abbeydale Road in Wembley.
The whole of the ground and first floors of the unit were destroyed by fire and part of the roof was also damaged. There were no reports of any injuries.
Station Commander Barry Davis, who was at the scene, said: “The fire was producing a significant amount of smoke, but crews worked quickly to bring the fire under control.
“One of the Brigade’s 32-metre turntable ladders was used at the scene to tackle the fire from height.”
The Brigade’s 999 Control Officers took 15 calls to the blaze.
The Brigade was called 2021 and the fire was under control by 2330. Fire crews from Wembley, Willesden, Hendon, North Kensington, Acton and Northolt fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.