Civil War battery on Helvear Hill, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1010169

Date first listed: 14-Feb-1995


Ordnance survey map of Civil War battery on Helvear Hill, St Mary's
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This copy shows the entry on 17-Dec-2018 at 19:53:37.


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 92335 12404


Legacy Record - This information may be included in the List Entry Details.

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.

The Civil War battery in this monument has survived well. Its situation, and the survival of extensive historical documentation giving the context in which it was built, demonstrate clearly the strategic methods employed by the Civil War military forces and the functions of batteries within them. These methods are also well illustrated by the complementary relationship of this monument to the other surviving breastworks and batteries along the north east coast of St Mary's.


Legacy Record - This information may be included in the List Entry Details.


The monument includes a gun battery dating to the English Civil War, situated on the north east end of the ridge forming Helvear Hill, overlooking the steep scarp to the north eastern coast of St Mary's in the Isles of Scilly.

The battery survives with a defensive earth and rubble bank and outer ditch along its northern side, fronting the crest of the hill's ridge and creating a right angled line facing the main fields of fire to the NNW and north east. The bank is up to 3m wide, 0.5m high on the inner side and 1.5m high on its outer side. Laid slabs from a stone facing are visible on part of the inner side of the bank. The bank extends for 14m along each of the principal NNW and north east flanks of the battery. Beyond these main flanks, at the western end of the battery, the bank curves south, then west, over a further 17m, while at the eastern end it curves east for a further 5m. The outer ditch measures up to 4m wide and 0.5m deep and extends around the outer edge of the bank on all sides except the short east-west length at the western end. The interior of the battery, enclosed by the bank, shows no evidence for artificial levelling of the slight slope at the top of the hill.

This battery forms part of an integrated system of Civil War coastal defences which survive extensively around St Mary's. These defences include breastworks bordering potential landing places and near important settlements and installations, coupled with a system of batteries commanding complementary fields of fire over the waters around much of the island's coast. The battery in this monument has a field of fire over the entrance to the important strait of Crow Sound, the main route of entry for shipping into the Scilly archipelago from the east. The battery was recorded, and its strategic position recognised, by the antiquary and historian, Revd. John Troutbeck, in 1796. This battery complements the fields of fire of other batteries in analogous locations on the successive headlands along the east and north east coast of St Mary's from Normandy Down to Bar Point, while most of the coast bordering Crow Sound is also defended by a breastwork, from 60m north east of this monument.

The modern riding trail marker post is excluded from the scheduling but the ground beneath is included.

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: 15378

Legacy System: RSM


Books and journals
O'Neil, BH St J, Ancient Monuments of the Isles of Scilly, (1949)
consulted 1994, Parkes, C., AM 107 for Scilly SMR entry PRN 7457, (1988)
Title: 1:2500 Ordnance Survey Map; SV 9212 Source Date: 1980 Author: Publisher: Surveyor:

End of official listing