TORY mayoral candidate Susan Hall today/Tuesday pledged to extend the Night Tube to boost London’s late-night economy. She said she would provide all-night services at the weekend on the Hammersmith and City line “as soon as possible” if elected – followed by the District, Circle and Metropolitan lines “when feasible”. Mayor Sadiq Khan, her Labour rival, tried to steal her thunder by immediately promising to do likewise if he wins a third term on May 2. The Night Tube currently operates on five “deep level” lines – the Victoria, Jubilee, Central, Piccadilly and Northern. Part of the London Overground – the former East London line - also operates night services.