Four fire engines and around 25 firefighters tackled a house fire on Grosvenor Road in Wanstead.
Part of the roof and loft conversion of a two-storey terraced house was damaged by fire. Two adults and two children left the house before firefighters arrived. There were no reports of any injuries.
The Brigade was called at 0520 and the fire was extinguished by 0701. Crews from Leytonstone, Woodford, Stratford and Leyton fire stations attended the scene.
The most probable cause of the fire was a lightning strike.