When the first section of the Chester Canal opened in 1775, the entrance lock was followed by a staircase of five locks. The Ellesmere Canal's 1793 Act authorised a canal from the Dee to the Mersey, totally independent of the Chester Canal. This was soon changed: the Wirral Line joined the Chester Canal below the middle lock of the stairacse, and the bottom two locks of the staircase were superceded by a new link, known as the Dee Branch. The Wirral Line was the only part of the Ellesmere Canal which was built to broad dimensions.