Cardiff Docks. which included the Port of Barry, were designated as a Class C by the Home Ports Defence Committee , later the Home Defence Committee in 1905. The defences were designed to deal with block ships and unarmoured cruisers. Barry Docks were the main point of export for Welsh Coal used extensively by the Royal Navy and shipping to coaling stations around the World.
By the end of the 19th Century, Cardiff was protected by two batteries,
- Nell’s Point Battery built between 1899 and 1900 which mounted two 6-inch Mark VII guns.
- Lavernock Battery which was originally built between 1865 and 1870 to mount four guns on Moncrieff mountings. Between 1900 and 1901 this was upgraded to mount two 6-inch Mark VII guns.