Six fire engines and 35 firefighters and officers tackled a shop fire in High Street, Ruislip last night.
The alarm was raised by people in a neighbouring shop when who noticed smoke in front of their own property.
When the first fire crews arrived they discovered the fire in the rear of the shop had spread to a flat above.
The shop and flat were both left severely damaged by the blaze but thankfully there were no injuries as nobody was inside the property at the time.
A smoke alarm was fitted, but it is not known if it operated.
A London Fire Brigade spokesperson said:
“It is important to make sure your smoke alarm is always working properly, and that the batteries have not been removed.”
"Everyone should have at least one smoke alarm on every level of their home and the safest option is have those linked together. This will give the earliest warning if there is a fire.."
The Brigade was called at 1920 and the fire was under control by 2256. Firefighters from Hillingdon, Ruislip, Harrow, Southall, Wembley, Hammersmith, and Stanmore fire stations attended the scene.
The cause of the fire is under investigation.