The importance of defending Portland Roads was well understood by Henry VIII who built two forts to cover the anchorage, Portland and Sandsfoot Castles.  

By the nineteenth century, the toll of ships wrecked on Chesil Bank led men to consider improving the shelter provided by the Roads.  

In 1848 the Government decided to partially enclose the bay and a scheme was devised for the defense of the new harbor to consist of a large citadel at the Verne, on top of Portland, batteries at East Wear and on the Inner Pierhead and forts on the Breakwater and the Nothe Headland with interlocking arcs of fire.

All, bar the Breakwater Fort, were complete by 1872 when the Prince of Wales, later to become Edward VII, arrived with the Royal Yacht, Victoria and Albert, to lay the completion stone.

The Breakwater Fort suffered problems with subsidence and was not finished until 1875 and did not become operational until 1895.

Portland Harbour became a base for the Royal Navy and home at various times to the Channel and Home Fleets.

In 1891 the Lancastrian engineer, William Whitehead, who had been developing the torpedo for the Austrian navy at Trieste, moved his factory to Weymouth.  

The Admiralty now recognized the vulnerability of its ships at anchor to the torpedo and decided to build two more breakwaters and complete the enclosure of the harbor.

Each pierhead on the new breakwaters was built as a small fort with its own gun emplacements.