The South Lines is a rock cut ditch with a profiled rampart and banquette which was designed to secure the south-western flank of the fortress from attack along the lower road from Folkestone. It extended from the north-eastern corner of the Citadel’s tenaille southwards down the steep slope to the Cliff edge. The South Lines form part of the set of Lines constructed to create an entrenched encampment or fortress on the hilltop to protect a large field force in garrison quarters who could not be accommodated in the Citadel and Drop Redoubt. The firepower was provided in the form of enfilade defence along the ditch from the South Lines Casemates constructed mid-way down the Lines, from where they afforded defence for the South Lines Bridge. Much of the ditch has been infilled. (location accurate to the nearest 1m based on available information)