Six fire engines and around 40 firefighters were called to a fire at a disused pub on Wood Lane in Dagenham.
A detached storage building was destroyed by fire. There were no reports of any injuries.
Station Commander Peter Cox, who was at the scene, said: “Crews arrived to see smoke which appeared to come from the roof of a disused pub, but on investigation firefighters discovered a small fire in a storage building next to the pub.
“Crews worked incredibly hard to quickly bring the fire under control and stop it from spreading to the pub.”
The Brigade was called at 0647 and the fire was under control by 0748. Fire crews from Dagenham, Ilford, Romford and Peckham fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.