The ditch and the rampart were constructed as part of the Napoleonic works on the fort between 1804 and 1810, though the vertical scarp revetment was not completed until a later phase of works was undertaken at the fort, and was likely largely complete by 1862. It is built in stock brick laid to English bond and where visible, the loopholes from the casemated galleries are built to a stepped exterior profile. (location accurate to the nearest 1m based on available information)