Fort Blockhouse Rebuilt and Expanded

1710s

Fort Blockhouse, the defensive position at the tip of the Gosport peninsula commanding the harbour entrance, was substantially rebuilt and expanded in the early eighteenth century. The original Tudor blockhouse had served its purpose, but the growth of the Royal Navy and the increasing importance of Portsmouth as the primary naval base demanded stronger defences. The rebuilt fort included improved gun batteries, barracks for the garrison, and reinforced earthworks designed to withstand bombardment from sea. The position was considered vital, as any enemy fleet attempting to enter Portsmouth Harbour would pass within close range of the fort's guns. Fort Blockhouse would continue to evolve over the following centuries, serving different military purposes as technology changed. In the twentieth century, it became the home of the Royal Navy's submarine service, housing HMS Dolphin, the submarine base that trained generations of submariners. The fort's long history spans the full arc of Gosport's military significance, from Tudor coastal defence to Cold War submarine operations. The site remains in military use today, though parts have been opened for heritage access.

Context

The early eighteenth century saw extensive investment in Portsmouth's defences during the wars with France under Louis XIV.

Impact

Fort Blockhouse became one of the most continuously garrisoned positions in England, serving military purposes for over 450 years.