Ten fire engines and around 70 firefighters dealt with a fire at a storage facility on Townmead Road in Fulham.
Station Commander Jonathan Parker, who was at the scene, said: "The fire damaged part of the sub-basement of the storage unit.
"Due to its location, we deployed a number of firefighters inside the building in breathing apparatus which was very labour intensive."
The Brigade was called at 2006 and the fire was under control by 2350. Fire crews from Wandsworth and surrounding fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.