Fort Blockhouse in Gosport holds the distinction of being believed to be the oldest continuously fortified military position in the United Kingdom still in active military use. First established as a blockhouse in 1431 under Henry VI, and later rebuilt in 1539 as an eight-gun battery by Henry VIII, the fort has evolved through five centuries of service. Surrounded by water on three sides, it commands the best views of Portsmouth Harbour's entrance. The site has transformed from a submarine base established in 1905 as HMS Dolphin to a training facility and now serves strategic military functions. Its historic structures and commanding waterfront location make it a significant landmark in Hampshire's maritime defence heritage.
