A huge explosion can be heard in a video of the fire which ripped through a factory and offices in Harrow .
Footage shows flames and huge plumes of smoke pouring into the night sky before the loud explosion is heard.
Firefighters at the scene in Chantry Place have said propane cylinders were on site, and set up a cordon and evacuated residents.
Network Rail say the fire was at a timber yard, while London Fire Brigade (LFB) say it was at a factory and offices.
As a result of the fire, rail passenger using the West Coast main line face severe disruption .
LFB was called to the scene shortly before midnight on Thursday (September 14). Eight engines and 58 firefighters attended, and had the blaze under control at 6.12am on Friday.
There are no reports of injuries.
The cause of the fire is not known.
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