Four fire engines and around 25 firefighters were called to a balcony fire on Jodrell Road in Bow.
Part of the balcony of a sixth floor flat was damaged by fire. One person left the property before the Brigade arrived. There were no reports of any injuries.
The fire was discovered by a resident who smelt burning and found a fire on their balcony. They attempted to extinguish the fire before leaving the property.
The Brigade's Fire Investigators believe the fire was accidental and caused by a cigarette which had dropped on to the balcony.
A London Fire Brigade spokesperson said: "It’s absolutely vital you ensure your cigarette is completely out when you’ve finished smoking it. Make sure smoking materials are out, cold and preferably wet them before throwing into a bin – never use a wastepaper basket.
“This is also a reminder to never try to tackle a fire yourself. Leave it to the professionals and call 999 as soon as you become aware of a fire in your home.”
The Brigade was called at 1214 and the fire was under control by 1316. Fire crews from Bethnal Green, Homerton, Leyton and Shoreditch fire stations attended the scene.