Post-medieval breastwork, curtain wall and associated defensive structures on the periphery of The Garrison, St Mary's
The Garrison on St Mary's, Isles of Scilly, represents one of the finest surviving examples of post-medieval coastal fortification in England. The defensive complex at these coordinates forms part of the remarkable circuit of breastworks, curtain walls, and associated military structures that encircle the headland known as The Garrison on the southwestern corner of St Mary's island. What makes this site exceptional is not merely the age and condition of its stonework but the almost complete survival of a continuous defensive perimeter that was developed and refined across several centuries of strategic military thinking. As a Scheduled Ancient Monument and a site of significant national importance, the fortifications offer visitors a rare opportunity to walk the full circuit of a post-medieval defensive landscape that has been comparatively little altered by modern development.
The origins of The Garrison fortifications stretch back to the late sixteenth century, when the threat of Spanish naval power made the Isles of Scilly a matter of serious strategic concern to the English Crown. Star Castle, the distinctive eight-pointed fort at the heart of the headland, was constructed in 1593 on the orders of Queen Elizabeth I, and the surrounding defensive lines were intended to protect and complement that central stronghold. The breastworks and curtain walls that form the outer perimeter were developed and extended primarily during the late seventeenth and early eighteenth centuries, during periods of renewed European conflict. The Act of Union and the wars of the age of Marlborough prompted significant upgrades to the existing earthworks and the addition of gun platforms and bastions designed to cover the approaches from the sea. The site saw ongoing military use well into the nineteenth century, and the layering of different periods of fortification is visible to the attentive visitor in the varying construction techniques and materials.
Physically, the defensive circuit is a deeply satisfying piece of historic engineering. The curtain walls are built of dry-laid and mortared granite rubite, the characteristic warm grey stone of the Scilly islands, and they rise to a commanding height along the most exposed sections of the perimeter. Gun embrasures and cannon platforms punctuate the wall at intervals, some still holding the iron cannon that were emplaced there in the eighteenth century, their muzzles pointing silently out toward the Atlantic. The breastworks along the landward and more sheltered sections have a lower, earthier character, their grassed-over profiles softened by centuries of weathering. The whole perimeter path is walkable and provides extraordinary views in every direction — out across the Roads to the Eastern Isles, northward toward Tresco and Bryher, and down into Hugh Town below.
The sensory experience of walking the Garrison walls is unlike almost anywhere else in the British Isles. The wind is a near-constant companion, carrying salt and the sharp smell of gorse and heather from the slopes below. In calm weather, the sound of the sea against the rocks far beneath the walls creates a low, rhythmic background, while seabirds — herring gulls, shags, and in season puffins on the outer islands — call from the rocky shores. The granite underfoot is uneven and weathered to a pale silver-grey, and the lichen-covered surfaces of the older sections of wall give the fortifications a great sense of organic age. In spring, the slopes below the walls are carpeted with wildflowers, and the rare and delicate flora that thrives in the mild Scillonian climate adds an unexpected softness to what is otherwise an emphatically martial landscape.
The surroundings of The Garrison fortifications encompass the whole southwestern promontory of St Mary's, the largest of the Isles of Scilly. Hugh Town, the island's principal settlement, sits at the narrow neck of land connecting The Garrison headland to the main body of the island, and its small streets of granite cottages, the town quay, and the Isles of Scilly Museum are all within easy walking distance. Star Castle itself, now a hotel, crowns the headland and can be visited or admired from the wall walk. The Hugh Town beaches — Town Beach to the north and Porthcressa Beach to the south — frame the approach to the headland and are exceptionally beautiful. The whole of St Mary's is a compact island that can be explored on foot or by bicycle, with the coastal footpath extending around much of the island beyond The Garrison.
For visitors, reaching The Garrison fortifications requires first getting to St Mary's. The island is served by the Scillonian III passenger ferry from Penzance during the summer season, a crossing of approximately two hours and forty-five minutes, as well as by Skybus flights from Land's End, Newquay, and Exeter airports throughout the year. Once on the island, The Garrison is reached on foot from the quay at Hugh Town in a matter of minutes, following the main street westward and ascending via the gated entrance to the headland. The wall walk is freely accessible during daylight hours and is well maintained, though some sections involve uneven ground and modest gradients that may present challenges for those with limited mobility. The best seasons to visit are spring and early summer, when the light is clear, the wildflowers are in bloom, and the island is busy enough to have good facilities but not overcrowded.
A particularly fascinating aspect of the site is its remarkable state of preservation, which owes much to the relative isolation of the Isles of Scilly and the absence of significant industrial or urban development pressure. Historic England has recognised the importance of the complex, and ongoing conservation work has helped stabilize and present the walls in a manner sympathetic to their historic character. The cannon along the walls are among the best-preserved in situ examples of their type in England, and the variety of gun platforms reflects the evolving artillery technology of the seventeenth and eighteenth centuries. The Garrison also carries Civil War associations, having been held for the Royalist cause after the fall of mainland England to Parliament — Prince Charles (later Charles II) briefly took refuge in the Scilly Isles in 1646, lending the site an unexpected connection to the most dramatic episode of seventeenth-century English history.