People have been evacuated from their homes in north west London after a huge blaze broke out at a warehouse.
More than 50 firefighters were sent to tackle the fire at a factory and offices in Chantry Place, Harrow.
Dozens of concerned residents called 999 after spotting the flames and huge plumes of smoke, while social media users reported hearing explosions.
London Fire Brigade said 12 people had been evacuated from nearby homes "as a precaution".
Station Manager Jason Jones said: "We have got a very well developed fire which is extremely visible from quite a way out.
"There are propane cylinders involved so a hazard zone has been set up as cylinders can explode when exposed to heat.
"The site is next to Headstone Lane train station and trains have been stopped.
"Crews are working hard to bring the fire under control."
A total of eight fire engines and 58 firefighters were sent to the scene after more than 30 emergency calls were received on Thursday, just before midnight.
A cordon was put in place on Headstone Lane.
People on a London Midland service from Euston to Milton Keynes had to be evacuated from the train at Headstone Lane, and were provided with taxis to get them to their destination.
The cause of the fire is not yet known.
Commuters are being warned of potential delays to their journeys due to the fire, as train services between Watford Junction and Euston are not running.
A spokesperson for Network Rail said: "Passengers wanting to travel on the West Coast Main Line and West London Line are urged to check with their train operator or nationalrail.co.uk before travelling as disruption and cancellations are to be expected throughout the day."