Four fire engines and around 25 firefighters attended a fire at a flat on Beardsfield in Plaistow.
Most of a ground floor flat in a four-storey black of flats was damaged by fire. One person was taken to hospital as a precaution to be treated for smoke inhalation.
The property where the fire occurred had no smoke detection fitted.
A London Fire Brigade spokesperson said: "This incident shows just how important it is to have working smoke alarms fitted on every level of your home.
“Smoke alarms give the earliest possible warning when a fire starts and we would urge everyone to make sure they have one fitted in every room where a fire can start except kitchens or bathrooms where heat alarms are more appropriate.”
The Brigade's Control Officers received around 13 calls about the fire.
The Brigade was called at 2154 and Control Officers mobilised crews from Plaistow, Stratford, East Ham and Leytonstone fire stations to the scene. The fire was extinguished by 2257.
The fire is being treated as accidental and is believed to have been caused by a naked flame being too close to combustion materials.