Four fire engines and 21 firefighters and officers were called to a fire at Leytonstone Underground Station.
Rubbish was alight and an internal chamber linking the eastbound and westbound tunnels was slightly damaged by the fire.
The Brigade was called at 0240 and the fire was under control at 0811. Fire crews from Leytonstone, Stratford, Leyton and Walthamstow attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.