The station is on the Victoria Line and the London Overground Gospel Oak to Barking Line , in Travelcard Zone 3 . It is the least used station on the Victoria Line with 6.179 million passengers per year . The station is on the Victoria Line and the London Overground Gospel Oak to Barking Line , in Travelcard Zone 3 and is the least used station on the Victoria line with 6.179 million passengers per year .