Four fire engines and around 25 firefighters tackled a fire at a metal scrap yard on Mitcham Road in Croydon.
A pile of scrap metal in open air was destroyed by fire. There were no reports of any injuries.
Station Commander Mike Dowden, who was at the scene, said: “The fire was producing a large plume of smoke, which has now subsided.
“An on-site mechanical digger was used to turn over the scrap metal, helping crews to access the fire.”
The Brigade was called at 0440 and the fire was under control by 0757. Fire crews from Croydon, Norbury, Mitcham and Wallington fire stations attended the scene.
The cause of the fire is under investigation.