Four fire engines and around 25 firefighters were called to a fire at a storage area on Bramley Road, Southgate.
The storage area, which was adjacent to a petrol station and supermarket, was destroyed by fire.
Southgate Watch Manager Andy Bathie, who was at the scene, said: “A passer-by called the Brigade after seeing flames coming from the storage area. When crews arrived, it was a fully developed fire and firefighters worked hard in difficult conditions to bring the fire under control.”
The Brigade’s 999 control officers received a total of 18 calls to the visible fire.
The Brigade was called at 0127 and the fire was under control at 0217. Fire crews from Southgate, Barnet, and Enfield fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.