Ruinious remains of a Tudor artillery fort, built circa 1541. Bastion earthworks were added in around 1623. Portland rubble core with remains of ashlar in parts. One of Henry VIII's coastal forts, built at a cost of £3887-4s-1d. Originally a central block of 2 storeys and basement, with NW entrance gate, and an octagonal gun-room on the seaward side. The outer walls with gatehouse remain in part, much decayed, but the gun-room has practically disappeared through coastal erosion. The entry front has remains of the left side of the gatehouse over an entry with straight-sided low arch, with remains of walling each side, unfaced. The right side has remains of walling to basement, ground and first floors, with substantial ashlar remnants to the upper level with 4 large openings to deep reveals on 4-centred heads over square openings, and very steep sloping sills. Beneath, in unfaced walling, are 6 lights to peaked heads, with 5 square-headed openings to the basement. The opposite flank has 4 deep casements, in some ashlar facing, above 4 openings to the main level; the basement level is below ground level on this side. Interior is completely unroofed and without floors or fittings except for remains of a fireplace and doorways at the seaward end. The building suffered early erosion, already referred to in 1584, was abandoned for military use in 1644-5, and used as a store until 1691. (Listed Building Report)
Despite some coastal erosion, Sandsfoot Castle survives comparatively well as a ruined structure and associated earthwork remains. The blockhouse represents one of the most substantial examples of this type of Tudor fortification to survive in an unaltered state and it also contrasts with the contemporary site at Portland Castle with which it was designed to guard the anchorage of Weymouth Bay. The ruins at Sandsfoot Castle display many significant architectural features and has attracted the interest of artists, who have recorded the condition of the site over a long period. The surrounding earthwork survives comparatively well and this, along with the interior of the site, is likely to contain additional buried remains and associated deposits which will contain important archaeological and environmental evidence relating to the monument and the landscape in which it was constructed. Sandsfoot Castle represents an early component of the coastal defences which were developed in order to defend the anchorage of Weymouth Bay and, subsequently, the harbour at Portland. Together, these coastal defences represent one of the most significant groups to survive in England.
The monument includes the surviving remains of Sandsfoot Castle, a Tudor artillery castle situated upon a prominent coastal headland in Weymouth Bay. The castle formed part of a chain of forts built along the south coast during the 1540s. Along with Portland Castle, it served to guard the anchorage between Weymouth and Portland. The castle is now ruined, but originally included a heavy gun emplacement, quarters for a garrison and a magazine. The surviving remains comprise a blockhouse or a rectangular two storeyed structure, set over a basement, with an integrated tower at the north western (landward) end. The walls of the blockhouse survive well, some almost to their original height, although much of the facing blocks from the outer walls has been robbed. The castle is a Listed Building Grade II star. An octagonal gunroom was situated at the seaward end and was recorded by J H Grimm in 1790, although this has since been lost to coastal erosion. By 1947 only the south western embrasure survived and this collapsed during the 1950s. The castle is protected on the landward side by an outer earthwork which survives along the north western, north eastern and south western sides. The earthwork includes a bank 5m wide and about 0.7m high and an outer ditch 5m wide and about 1.5m deep. The earthwork is first recorded in a survey of 1623, when orders were made to repair the castle. A stone structure is also mentioned in the 1623 report, but this no longer survives as an upstanding feature and is most likely to have been built upon the bank. The presence of the castle is recorded by Lord Russell's Survey of 1539, although it was not mentioned in the list of the Royal fortresses compiled in 1540 and so may not have been completed at this time. The castle is known from documentary sources to have cost 3887 pounds, 4 shillings, 1 pence, and a gunner had been appointed by 1541. The castle was in poor repair by 1584, as the eastern end had become undermined by the sea. Repair work was initiated to the gun platforms, stables and the gate to the outer ward and a new bridge was constructed to the outer gate. Further repairs were undertaken in 1610-11 and dilapidation noted in the survey of 1623, when it was recommended that the upper gun platform should be dismantled. At this time, the armament included ten pieces of ordnance and the garrison comprised a Captain, Master Gunner, four gunners and three men. The castle was held by Royalists during the Civil War, but was later abandoned as a fort, although it continued in use as a storehouse until at least 1691. During World War II, Sandsfoot Castle is thought to have housed a Light Anti- aircraft battery and formed part of the wider defences constructed at this time in order to protect Portland Harbour. The remains of the south western embrasure are now located on the beach to the south east of the standing remains and this stonework is also included within the scheduling. (Scheduling Report)