Four fire engines and around 25 firefighters tackled a fire involving outbuildings and shrublands on West End Road in Ruislip.
An area, measuring around 400 sqm, was destroyed by the fire. There were no reports of any injuries.
Ten gas cylinders were cooled to an ambient temperature as a precaution, as some cylinders can explode when exposed to heat.
The Brigade was called at 1704 and the fire was under control by 1853. Fire crews from Northolt, Ruislip and Southall fire stations attended the scene.
The cause of the fire is under investigation.