Barrow was designated as a Class C defended commercial harbour.
Barrow-in-Furness or Barrow, had one of the largest UK steel works in the latter quarters of the 20th Century. This led to the development of shipbuilding including warships. Barrow became a specialist location for the building of submarines. Although classified as a naval port, it was the factories in Barrow producing armaments and warships that required a limited coast defence.
The Barrow Ship Building Company was taken over by the Vickers Ship Building and Engineering in 1897. The First Royal Navy Submarine, Holland 1 was built here in 1901 by Vickers. Barrow remained an important location for the building or warships and making of armaments. BAE Systems have now taken over much of the works and in 2023 the AUKUS agreement saw Barrow identified as 0ne of the locations to to be used to built part of the the new Australian Nuclear Submarine Fleet.
From 1908 Barrow was also a site for the building of military airships. Vickers, later Vickers-Armstrong Limited, built the first airship by 1910 in Barrow-in-Furness.
There were initially plans to built a battery with two 9.2-inch Mark X gun and another with two 6-inch Mark VII guns. Both Batteries were to be built on Walney Island. The Armaments Committee dismissed the two 9.2-inch guns in 1905 and recommended three 6-inch Mark VII BL guns for Walney Island. No defence Electric Lights were thought to be required at that time.
The 6-inch Mark VII Walney Battery was built by 1911 and manned by the Lancashire and Cheshire Royal Garrison Artillery. In 1914 a further battery was added, Hilpsfort Battery, on the South end of the Island.