The first artillery introduced in coastal defence batteries had a limited range, and they therefore tended to be concentrated on the shore line to maximise their effective range. At this time the artillery was largely mounted in gun towers or blockhouses, which provided all round defence. The range of artillery was so limited that Land Fort were not usually required to protect harbour and dockyards.
During the Napoleonic War various defence lines were built, such as the Gosport Lines and Stoke Bay Lines in Portsmouth and Great Lines of Chatham. However, it was not until the Royal Commission Report published on 7th February 1870 that significant consideration was given to the need to establish land forts to protect the approaches to the major dockyards and harbours.
A number of large forts were to be built on the outskirts of major harbours. for example in Portsmouth, we have the Portsdown Hill Line with five forts and one redoubt, and the Gosport Advances Line with five forts. These extended fortifications were replicated in different form in overseas possession, An example of this is the building of Victoria Lines in Malta, with three forts and artillery batteries. The purpose of these lines, including the Dweja Lines, was to keep hostile artillery out of range of the main dockyard at Valetta.