Sully Island

Sully Island is a small tidal island of about six hectares in the Vale of Glamorgan, four hundred metres off the Bristol Channel coast. It lies midway between Penarth and Barry, ten kilometres south of Cardiff, and is one of forty-three unbridged islands in Britain that can be reached on foot at low tide. The island is registered as a Site of Special Scientific Interest and has a long history tied to the nearby hamlet of Swanbridge. A rocky causeway appears for roughly three hours either side of low tide, linking the island to the mainland when the tide is out. The Captain’s Wife pub in Swanbridge marks the usual starting point for visitors walking across. The island’s past includes a Norman pirate called Alfredo de Marisco, known locally as the Night Hawk, who used it as a base in the 13th century. Earlier, Romans and Vikings visited the island, and archaeologists have found traces of a Saxon fort and a Bronze Age burial mound. For centuries Swanbridge served as a busy harbour, though little remains today except old mooring rings and records of smuggling. In 1569 officials seized twenty-eight thousand pounds of cheese and eighty barrels of butter landed illegally, and in 1658 the port was used to land people described at the time as undesirables. A wrecked Antarctic survey ship, the SY Scotia, came to grief nearby in 1916, and local children collected coal from its cargo for weeks. Visitors find a low, sandy island covered mainly in coarse grass with a small reed bed in a damp central hollow. The sea cliffs expose red Triassic mudstones and sandstones laid down about two hundred million years ago, resting on older Carboniferous limestone. The waters around the island hold cod, whiting, pouting, dogfish, conger eel and bass, and rare plants such as bee orchid and adder’s tongue fern grow on the foreshore. The island has no trees and only scattered bushes, making the open grassland and the rocky shoreline the main features. From the causeway the views stretch across the channel to Penarth and Lavernock, with the distant hills of the South Wales valleys on clear days.