Six fire engines and around 40 firefighters were called to a barn alight on Sevenoaks Road in Pratts Bottom.
One single storey barn was destroyed by the fire. Crews cooled one propane cylinder to an ambient temperature as some cylinders can explode when exposed to heat. There were no reports of any injuries.
The Brigade was called at 2338 and the fire was under control by 0226 (Sunday). Fire crews from Orpington, Biggin Hill, Bromley and Addington fire stations were at the scene.
The cause of the fire is under investigation.