Civil War battery at Carn Leh, St Mary's


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


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The building or site itself may lie within the boundary of more than one authority.

Isles of Scilly (Unitary Authority)
St. Mary's
National Grid Reference:
SV 91318 09865

Reasons for Designation

The Isles of Scilly, the westernmost of the granite masses of south west England, contain a remarkable abundance and variety of archaeological remains from over 4000 years of human activity. The remote physical setting of the islands, over 40km beyond the mainland in the approaches to the English Channel, has lent a distinctive character to those remains, producing many unusual features important for our broader understanding of the social development of early communities. Throughout the human occupation there has been a gradual submergence of the islands' land area, providing a stimulus to change in the environment and its exploitation. This process has produced evidence for responses to such change against an independent time-scale, promoting integrated studies of archaeological, environmental and linguistic aspects of the islands' settlement. The islands' archaeological remains demonstrate clearly the gradually expanding size and range of contacts of their communities. By the post- medieval period (from AD 1540), the islands occupied a nationally strategic location, resulting in an important concentration of defensive works reflecting the development of fortification methods and technology from the mid 16th to the 20th centuries. An important and unusual range of post- medieval monuments also reflects the islands' position as a formidable hazard for the nation's shipping in the western approaches. The exceptional preservation of the archaeological remains on the islands has long been recognised, producing an unusually full and detailed body of documentation, including several recent surveys. Civil War fieldworks are earthworks which were raised during military operations between 1642 and 1651 to provide temporary protection for infantry or to act as gun emplacements. The earthworks, which may have been reinforced with revetting or palisades, consist of earth and rubble platforms or banks and ditches. The Civil War fieldworks of the Isles of Scilly form a major part of the 150 surviving examples of fieldworks recorded nationally. They present an unusually complete system of fortifications from this period, both in the surviving range of fieldwork types represented and in the surviving pattern of their strategic disposition. Three main types of Civil War fieldwork have been recognised on the Isles of Scilly: breastworks, batteries and platforms; these could be deployed separately or in combination to form a defensive complex. Breastworks, which on the Isles of Scilly run beside the coastal cliff edge, consist of an earth and rubble bank, up to 4m wide and nearly 2m high but generally much smaller, usually accompanied by a ditch on the landward side. Sixteen surviving examples are recorded on the island. Batteries are levelled areas or platforms, generally up to 20m across, situated on a hilltop or terraced into a slope to serve as gun emplacements. They vary considerably in size and shape and are usually partially or wholly enclosed by a bank, occasionally incorporating one or two outer ditches. Twenty batteries survive on the Isles of Scilly, several connected by breastworks. Adjacent to some batteries are examples of the third fieldwork type, platforms. These are partly terraced into, and partly out from, sloping ground and represent sites of lookouts and temporary buildings. Eight such platforms, measuring up to 12m by 8m in size, are known to survive on the islands. These fieldworks and fieldwork complexes were occasionally associated with other classes of defensive monument on the islands, including earthen artillery forts and blockhouses. The fieldworks were designed to defend the deep water approaches to the islands, especially St Mary's where most examples are found. Fieldworks are also known from Tresco, Bryher, Samson, St Agnes and Gugh. The circumstances of their construction are recorded in contemporary historical documents which indicate most were built by the Royalist forces which controlled the islands for the entire Civil War period except during 1646-8.

This Civil War battery at Carn Leh has survived substantially intact. Although parts of one outer bank have been lost to coastal erosion, its internal area remains complete, retaining a good example of a gun pit. Its situation and the survival of documentation giving the historical context in which this battery was built demonstrates clearly the strategic methods employed by the Civil War military forces and the function of batteries within them. This is also illustrated by the survival of the complementary Civil War batteries, one on the opposite side of Old Town Bay and the others on Peninnis Head guarding the approach to St Mary's Sound.


The monument includes a gun battery dating to the English Civil War situated at Carn Leh, a small rocky peninsula defining the southern edge of Old Town Bay on St Mary's, in the Isles of Scilly.

The battery extends across the south east sector of the small coastal shelf bordering the massive granite outcrop named Carn Leh. The battery's internal area measures 40m long, NW-SE, tapering in width from 20m at its south east end to 10m wide at its north west end. It is defined to the NNW by Carn Leh and to its south east by the rocky shoreline. Between those natural features, its internal area is defined by two earth and rubble banks. The western bank extends for 20m SSE across the shelf from the Carn Leh outcrop to a small outcrop beside the foreshore and forms a scarp 0.5m high facing west, gently dipping to ground level to the east over a width of 2m. The eastern bank follows the shallow `S-shaped' curve of the slight coastal cliff, extending for 30m south east from near the eastern face of the Carn Leh outcrop to the eastern tip of the small peninsula. This eastern bank has lost its outer, north eastern, side due to coastal erosion of the underlying sea cliff; its inner slope is now visible up to 0.5m wide and 0.5m high. This bank is accompanied by a ditch, up to 1m wide and 0.4m deep, along its inner, south west, side. Within the broader south east end of the battery, adjacent to the end of the coastal bank and ditch, is the slightly sunken gun pit, visible as an oval hollow measuring 9m NW-SE by 6m NE-SW and 0.4m deep, defined along its north east edge by an additional bank, 1.5m wide and 0.5m high.

The battery at Carn Leh commanded the entrance to Old Town Bay, which contains one of the principal harbours and settlements on the main populated island of St Mary's, the military and administrative focus of the Isles of Scilly during the Civil War. This battery is complemented by another Civil War battery on the opposite side of the entrance to Old Town Bay, while other contemporary batteries located on Peninnis Head, south of Carn Leh, extended the field of fire to the southern approaches to St Mary's Sound.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


consulted 1993, Waters, A., AM 107 relating to Cornwall SMR entry for PRN 7415, (1988)
consulted 1993, Waters, A., AM 107 relating to Cornwall SMR entry for PRN 7555, (1988)
Title: 1:10000 Ordnance Survey Map; SV 90 NW Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Map; SV 9109 Source Date: Author: Publisher: Surveyor:


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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