Four fire engines and around 25 firefighters were called to a flat fire on Hanover Park in Peckham.
Part of a four-roomed flat on the third floor of the building was damaged by fire. Firefighters wearing breathing apparatus assisted five people to safety via an internal staircase. There were no reports of any injuries.
A London Fire Brigade spokesperson said: “There were smoke alarms fitted inside the affected flat, but they didn’t raise the alarm.
“This incident is a reminder about the importance of ensuring you have working smoke alarms in every room where a fire could start in your home, plus a heat alarm in the kitchen. Make sure to test them regularly.”
The Brigade was called at 0037 and the fire was under control by 0146. Fire crews from Peckham, New Cross, Old Kent Road and Brixton fire stations attended the scene.
The cause of the fire is believed to have involved an extractor hood.