Four fire engines and around 25 firefighters were called to a fire in a lean-to behind a mosque in Clevendon Road, Penge.
The single storey lean-to was destroyed by fire. Two gas cylinders were removed and cooled to ambient temperatures, as some cylinders can explode when exposed to heat. There were no reports of any injuries.
The Brigade was called at 1533 and the fire was under control by 1613.
Fire crews from Beckenham, Woodside, Forest Hill and Bromley stations were at the scene.
The cause of the fire has been recorded as undetermined.