If the Chelseaâ `` Hackney line is built then it will relieve a lot of congestion on the Victoria line . It will offer an alternative route across Central London between Victoria and King 's Cross St. Pancras . If the Chelseaâ `` Hackney line were to be built it would relieve a lot of congestion on the Victoria line , offering an alternative route across Central London between Victoria and King 's Cross St. Pancras .