HM Fort Roughs

HM Fort Roughs is a naval fortress built on a sandbar in the North Sea off the coast of Suffolk. The structure consists of two hollow reinforced concrete towers standing on a rectangular pontoon base with multiple levels containing crew quarters and equipment rooms.

The British military built the fortress in 1942 as part of a defensive line against German aircraft attacking ships in the Thames Estuary during World War II. After the war ended, the military abandoned the installation in 1956 and it remained unoccupied for years before being claimed by civilians in 1967.

Fort Roughs transformed into an independent territory when Paddy Roy Bates occupied it in 1967 and established the Principality of Sealand.

The fortress sits roughly 11 kilometers off the Suffolk coast and appears on navigational charts as a reference point for vessels heading toward Felixstowe or Harwich. Access is only possible by boat and depends on tidal conditions and weather in the North Sea.

The entire installation was built on land, then towed on pontoons into open water and deliberately sunk onto a sandbar so that the towers remained above sea level. The weight of the construction reached roughly 4,500 tons, requiring four tugboats to move it to its final position.