In 1905 (and again in 1965), plans were made to extend it the short distance south under the River Thames to Waterloo, but this never happened.
V roce 1905 (a znovu také v roce 1965) bylo navrženo prodloužit tento krátký úsek dále na jih pod Temži do stanice Waterloo, ale tato eventualita však nebyla nikdy provedena.