Civil War breastwork and battery 60m east of Carn Nore, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1014242

Date first listed: 09-May-1995


Ordnance survey map of Civil War breastwork and battery 60m east of Carn Nore, St Mary's
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The building or site itself may lie within the boundary of more than one authority.

District: Isles of Scilly (Unitary Authority)

Parish: St. Mary's

National Grid Reference: SV 92731 10540

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 islands. 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.

The Civil War breastwork and battery in this monument bordering Porth Hellick have survived reasonably well. Despite truncation by coastal erosion at each end of the monument, their situation and the survival of extensive historical documentation giving the context in which they were built, demonstrate clearly the strategic methods employed by the Civil War military forces and the function of breastworks within them. These methods are also well illustrated by the complementary relationship of this monument to the other surviving breastwork and battery along the north east side of Porth Hellick.


The monument includes a length of defensive bank and ditch, called a breastwork, dating to the English Civil War, which extends along part of the north east side of Porth Hellick on the south eastern coast of St Mary's in the Isles of Scilly. At the ESE end of the breastwork is a Civil War gun battery, positioned by the north east mouth of the bay. The breastwork survives as a turf-covered earth and rubble bank, up to 2m wide and 0.6m high, with slight traces of a ditch, up to 1m wide and 0.1m deep, along the landward side of the bank. The breastwork extends on an almost straight WNW-ESE course, running immediately behind the coastal cliff for 30m between Carn Nore and Porth Hellick Point on the north east side of Porth Hellick. The WNW end of the breastwork terminates where subsequent erosion of the coastal cliff has cut across its line. At its ESE end, the breastwork diverges slightly from the cliff edge to terminate 0.5m before meeting a second, similar earth and rubble bank which defines the seaward defensive edge of the battery. The battery's bank, up to 1.75m wide and 0.5m high, curves south from the breastwork, returning over 5m to the edge of the coastal cliff, then it curves again to extend ESE, behind the cliff edge, for a further 8.75m to the point where another incursion of the cliff has truncated its course. The breastwork and battery in this monument form part of an integrated system of Civil War coastal defences which survive extensively around St Mary's. In the vicinity of this monument, the defensive line along the north east side of Porth Hellick is continued, from 57m to the WNW, by a second surviving length of breastwork. A second Civil War coastal gun battery is also located at a higher level among the outcrops overlooking Porth Hellick Point, 60m ENE of the battery in this monument.

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: 15359

Legacy System: RSM


consulted 1994, Waters, A., AM 107 for Scilly SMR entry PRN 7529, (1988)
Title: 1:2500 Ordnance Survey Map; SV 9210 Source Date: 1980 Author: Publisher: Surveyor:

End of official listing