Six fire engines and around 40 firefighters tackled a fire at a disused pub on Wood Lane in Dagenham.
The whole of the roof of the building was destroyed by fire. There were no reports of any injuries.
Firefighters carried out a search of the property and remained on scene throughout the night damping down remaining hot spots.
The Brigade was called at 0052 and the fire was under control by 0313. Fire crews from Dagenham, Romford, Hornchurch, Ilford and Greenwich fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.