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Little now remains of Sandown Castle, an artillery fort built by Henry VIII to protect the northern end of the Downs. During the Second Civil War the castle held out for three months against a Parliamentary siege and later saw brief action during the Anglo-Dutch Wars. By the mid-nineteenth century it had been undermined by coastal erosion and was demolished.



Sandown Castle was the most northerly of a chain of fortifications built to defend the Downs, the stretch of water between the Goodwin Sands and the Kent coast which was one of the few safe anchorages for ships in the eastern English Channel. Furthermore, the three mile long shingle beach that extends along the coast was ideal for beaching small vessels. Together these made it an ideal place to land an invading army and accordingly it was identified as a weak spot by Henry VIII's Commissioners when reviewing coastal defence arrangements in light of deteriorating relations with the continental powers. Accordingly £27,092 was spent building defences along the entire stretch of coastline. The primary fortification was Deal Castle but this was augmented by a further two masonry castles, Sandown and Walmer, along with four earthwork bulwarks and a rampart and ditch which ran the entire length of the beach. Work on Sandown Castle in April 1539 and continued through to Autumn 1540.


The castle was almost identical in plan to Walmer Castle. It was constructed to a concentric design with a central circular tower surrounded by four lower rounded bastions. This provided three tiers of guns able to fire out over the beach and anchorages. In total there were 39 gun openings with a further 31 for handguns. A dry moat surrounded the castle which was crossed via a drawbridge on the landward side.


The invasion fears of the 1540s passed without major incident but Sandown Castle remained garrisoned. It would have stood on alert as the Spanish Armada passed by in 1588 and hosted a visit by Queen Elizabeth I during that crisis.  Thereafter the three Downs castles remained in use and were still active in the seventeenth century when, during the First Civil War, they were held by Parliament. Throughout the war, the three fortifications were deemed vital as their guns protected the Parliamentary controlled naval ships that operated from the sheltered waters of the Downs.


The Navy’s support for Parliament wavered in 1648 during the Second Civil War. After expressing sympathetic Royalist views, the regional commander – Vice Admiral Batten - was replaced by Colonel Rainsborough. This prompted a mutiny and the Downs based Navy defected to the Royalist cause. The three Downs castles were seized and garrisoned for the King. Parliament dispatched Colonel Rich to quell the uprising and capture the castles. Walmer was besieged first and fell on 12 July 1648. Deal lasted until 23 August 1648. Sandown held out until early September when a lack of supplies forced it to capitulate.


The Downs continued to serve as an important anchorage throughout the rest of the seventeenth and eighteenth centuries and accordingly Sandown Castle, along with the other Downs forts, continued to be garrisoned. During the Anglo-Dutch Wars, Sandown Castle reportedly opened fire upon a man-of-war attacking an English craft just off shore. However, by the latter half of the eighteenth century coastal erosion was starting to threaten the structure.  In 1785 water broke into the dry moat undermining the castle's foundations. Repairs were made in 1808 but they failed to stabilise the structure. This, coupled with a serious fire, meant the structure was assessed as beyond repair and in 1863 it was sold for building materials. By 1882 it has been largely demolished and what remained was buried/incorporated into the local sea defences in 1979. Today little is visible of Sandown Castle as the remains have been buried.





Allen, R (1976). English Castles. Batsford, London.

Colvin, H.M (1986). The History of the King's Works, Vol 4. HMSO, London.

Harrington, P (2007). The Castles of Henry VIII. Osprey Publishing, Oxford.

Historic England (2015). Sandown Castle, List entry 1005147. Historic England, London.

Johnson, P (2006). Castles from the Air: An Aerial Portrait of Britain’s Finest Castles. Bloomsbury, London.

King, C.D.J (1983). Castellarium anglicanum: an index and bibliography of the castles in England, Wales and the Islands.  Kraus International Publications.

Morley, B.M (1976). Henry VIII and the development of coastal defence. HMSO, Worcester.

Saltar, M (2002). The castles of Kent, Surrey and Sussex. Folly Publications, Malvern.

Saunders, A.D (1966). Coastal Defences since the introduction of artillery.

What's There?

Sandown Castle has suffered from coastal erosion, neglect and demolition meaning very little evidence of the structure is now visible.  Most of the surviving remains have been buried or incorporated into the sea defences.

Sandown Castle. What little survives of the castle has been buried.

Deal Defences. Seven fortifications were built to protect the Downs; Sandown Castle, Great Turf bulwark, Little Turf bulwark, Deal Castle, Great White bulwark, Black bulwark and Walmer Castle. In addition the entire beach was protected by a three mile long earthwork rampart and ditch. Maintenance on the earthworks ceased after the invasion scares of the 1540s passed.

Beach. The defences at Deal were to secure the three mile long single beach that offered an idea landing site for an enemy force. It is likely elements of the Roman army landed at this very site in AD 43.

Getting There

The site of Sandown Castle is found at the northern end of Sandown Road. The site is not sign-posted. On-road car parking is possible.

Sandown Castle

CT14 6QU

51.238389N 1.402142E