The Lower Lines formed a key part of the defences of Chatham Dockyard during the early part of the nineteenth century. While they were never used in combat, they became the focus for siege training during the later part of the century, and for the development of innovative new military technologies by the Royal Engineers. Latterly they were repurposed during the Second World War as part of the land defences for the Nore Command.

The archaeological work undertaken between 2007 and 2009 focussed on two sites, at Mid Kent College and the Black Lion Leisure Centre. This work allowed study of the defences, but also provided an opportunity to investigate how the Royal Engineers were using the area. They constructed elaborate siege exercises, involving many hundreds of men while also experimenting with new technologies such as electric searchlights. The archaeology together with contemporary records allow an intimate picture of what was taking place on the site throughout the nineteenth and into the twentieth centuries.