Four fire engines and 21 firefighters and officers were called to a fire in a building used as a suspected cannabis factory in Eastbourne Road, Brentford this morning.
Part of the first floor of the detached property of two floors was damaged by the blaze.
London Fire Brigade spokesperson said:
"Cannabis factory fires can be very severe because of the way criminals use unsafe wiring to illegally obtain electricity in order to grow the plants.
"They're often in top floors or lofts which means when a fire takes hold it spreads, destroying roofs and damaging neighbouring buildings.
"Firefighters can also be exposed to risks when dealing with the fires because of bad wiring and booby traps at some of the properties.
"It's important that people know the key signs and inform the police so that they can act swiftly to prevent these dangerous fires."
The Brigade was called at 0733 and the fire was under control at 0928. Fire crews from Chiswick, Ealing and Heston fire stations attended the scene.
The cause of the fire is under investigation by the police and fire officers.