These forts are located along Portsdown Hill overlooking Portsmouth, and were a response to advancing weapons technology. This new technology made it possible for shelling accurate over a number of miles to take place. The forts were intended to prevent a hostile force landing further along the coast, approaching Portsmouth from the mainland, taking the tactical high ground to the north of the dockyard. As such, the forts are designed so that all of their main weapons face inland, protecting Portsmouth from the rest of England.