Four fire engines and around 25 firefighters were called to a fire at a flat above a shop on York Mews in Ilford.
Most of a first floor flat was damaged by the fire and part of a second floor flat was also damaged. There were no reports of any injuries.
The fire was spotted by police officers attending an incident nearby. They saw smoke issuing from the property, called the Brigade and alerted residents.
The Brigade was called at 1844 and the fire was under control by 1948. Fire crews from Ilford, Stratford and East Ham fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.