Four fire engines and around 25 firefighters tackled a maisonette fire on McIntosh Close in Wallington.
Half of a second-floor maisonette was damaged by fire. A person was taken to hospital by London Ambulance Service crews after suffering from smoke inhalation.
The Brigade’s 999 Control Officers took 11 calls to the blaze.
A London Fire Brigade spokesperson said: “This incident is a reminder of just how important it is to have working smoke alarms in your home. Smoke alarms fitted in the property alerted residents to the blaze.
“Smoke alarms give the earliest possible warning when a fire starts. We encourage everyone to have smoke alarms fitted in every room where a fire could start.
“It’s also a good idea to have a heat alarm fitted in your kitchen. Fitting a heat alarm in your kitchen will give you warning of an increase in temperature caused by a fire but will not be set off by cooking fumes.”
The Brigade was called at 1558 and the fire was under control by 1708. Fire crews from Wallington, Croydon, Purley and Norbury fire stations attended the scene.
The cause of the fire is under investigation.