Calshot Castle

Calshot Castle stands on the narrow Calshot Spit where Southampton Water meets the Solent. Built between 1539 and 1540 for Henry VIII, it was one of four Device Forts designed to guard against invasion. The castle had a central keep, curtain wall, moat and an early garrison of sixteen men with up to thirty-six guns. It survived the English Civil War and was modernised in the 1770s. Later it served as a coastguard station against smuggling in the 19th century. The fort’s history reflects changing threats from France and evolving defences. In 1894 it was rearmed with a new coastal battery and a boom across the water to block enemy ships. During the First World War it became a seaplane base, hosting anti-submarine patrols and later the Schneider Trophy air races. By the Second World War it was rearmed again, though seaplanes soon made it obsolete. Visitors today find the restored 16th-century keep and curtain wall beside later military buildings. The central tower houses two quick-firing guns on its roof, and the outer walls show 18th-century alterations. The spit offers views across the Solent and towards the Isle of Wight. The site is open under English Heritage and remains a well-preserved example of Henry VIII’s Device Forts.