Fort Farningham formed part of a scheme implemented in the 1890s for the land defence of London against the possibility of a Continental invasion. The Farningham site, with its semi-circular rampart, was built in the form of an infantry redoubt and its design may have been influenced by the Twydall Profile as used in the northern sector of the Chatham ring fortress in 1885/6. As with most of the other permanent sites, this was both a defensive position and a store for the ammunition to be used in the line and for a reserve of tools needed by contractors to construct the fieldworks. The permanent sites were labelled ‘mobilisation centres’ in contemporary Parliamentary statements.