London Fire Brigade (LFB) were called at 7.58pm and attended the fire, with 12 fire engines and 81 firefighters, at two storey flats above shops in Preston Road.
One of the flats has been gutted by the fire and has extensive damage to the roof after half of it caught alight.
The fire spread to flats either side of the property, but no one was injured and one person left the building before LFB arrived.
Footage shows crowds of people watching on as LFB used fire hoses to spray water onto the flames in the flat.
The incident, which required 12 fire engines and 81 firefighters, was over shortly after midnight, at around 12.07 on Friday morning (August 12).
The cause of the fire is under investigation.