Eight fire engines and around 60 firefighters tackled a fire at a range of houses on Melford Road in Forest Hill.
The fire originated in a mid-terraced house and spread to adjoining properties. The whole of the first floor and the roof of a house were destroyed by fire. Half of the first floor of an adjoining property was also damaged and the roof was destroyed by fire. Half of the roof and part of the first floor of an adjacent property on the other side was also damaged in the blaze. Four people left the building before the Brigade arrived. One woman was treated on scene by London Ambulance Service crews.
A London Fire Brigade spokesperson said: “There were smoke alarms in this property, but they failed to alert the residents to the fire.
"We urge people to have working smoke alarms on every level of your home and to test them regularly. Smoke alarms will give the earliest possible warning if a fire breaks out in your home.
"Ideal spots for smoke alarms include rooms where you leave electrical equipment running like satellite boxes, computers or heaters; any room where you smoke, and anywhere you charge your mobile or laptop.
“As a minimum you should have smoke alarms on every floor - in the hallways and the rooms you use the most, plus a heat alarm in the kitchen and the bathroom. They should be tested regularly."
The Brigade was called at 0704 and the fire was under control by 0916. Fire crews from West Norwood, New Cross, Peckham, Norbury and surrounding fire stations were at the scene. The cause of the fire is under investigation.
The Brigade's Fire Investigators believe the cause of the fire was accidental and due to combustible materials being placed too close to a heat source.