Civil War battery and 18th century watch house on Mount Todden, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1015658

Date first listed: 07-Oct-1976

Date of most recent amendment: 21-Jan-1999


Ordnance survey map of Civil War battery and 18th century watch house on Mount Todden, 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 92974 11548


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 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 battery and 18th century watch house on Mount Todden survive well, forming an integral part of the 17th-18th century defensive systems whose overall survival on Scilly is unusually extensive. The aspect and elevated situation of the battery and watch-house gave them an unusual and key role in the application of those defences, demonstrating clearly the organisational and strategic methods employed by the military forces of that period. The continued strategic importance of this location in the evolving defences is also evidenced by its repeated military occupation from the 17th to mid-20th centuries.


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


The monument includes a large 17th century battery containing an 18th century stone-built watch house, situated on top of Mount Todden, a prominent rounded spur on the east coast of St Mary's in the Isles of Scilly. The battery also includes the foundation of a World War II generator-housing within its south east sector. The battery is visible as a subtriangular enclosure, up to 28m across internally, behind the crest of the spur's steep north east coastal slope. The enclosure is defined by an earth and rubble bank, generally 5m wide, 0.3m to 0.8m high internally and 1m to 2m high externally, with rounded corners facing south west, NNW and ESE. It has a 7.5m wide entrance gap on the west with an inturned terminal to the bank on the north. Both northern and southern entrance terminals are revetted by edge-set slabs with wedge marks along their edges, a splitting-method used prior to AD 1800. The battery interior is levelled, merging with the external ground level on the west but raised to 1.7m above it on the north east. A surface hollow behind the battery's ESE corner continues 1.3m into the inner face of the bank as a recess 3.5m wide, considered to be the site of a former gun platform whose demolition has left a scatter of granite blocks behind the recess, some with dressed faces. The watch house, roughly central within of the enclosure, survives as a rectangular building 3.5m north east-south west by 2m north west-south east and 1.8m high internally, with an entrance on the south west. Its north west wall is formed by a single massive 1.6m wide edge-set boulder projecting slightly beyond the building's north east end. The other walls are generally 1m thick and faced on each side by neat granite rubble, laid to course and mortared using the local subsoil, called ram. The south east wall has an upper course of larger slabs which project slightly into the interior to support a roof of six slender wedge-split slabs laid side-by-side. The north east wall rises 1.6m high, leaving a 0.3m high lookout gap below the roof. The south west wall, just beyond the roofed area, rises 1.2m high with an entrance gap 0.85m wide to the north west boulder wall; a vertical slot in the boulder's face indicates the entrance was formerly closed by a door. The upper surface of the roof and walls have a shallow-domed turf-covered rubble capping. Other features occur on the boulder forming the north west wall of the watch house. These include a vertical groove in the outer face of the projecting north east end, considered to have held a flagpole whose stays were secured by ring-headed iron pegs, one of which survives forward of the groove, lead plugged through the slab, with broken stumps of three more behind the groove. Within the watch house, the inner face of the boulder has a small rock-cut candle-holder, visible as a narrow ledge with a slight central pit below a vertical groove. Nearby, incised graffiti on the boulder's inner face includes the markings `WW 1809' and a group containing a Union Flag on a pole, a Royal Ordnance arrow, the date `1914' and the initials `JP'. Close to the south east of the watch house is the flat rectangular concrete raft of a small military generator building used during the World War II, since demolished; the raft has a small raised plinth in its south east half. Concrete rubble from the demolished walls is spread on the battery's south east bank. The battery and watch house occupy one of the most elevated situations on the east coast of St Mary's, with an uninterrupted field of view across the maritime approaches to the Isles of Scilly, extending across to the mainland in clear conditions. Their position complemented the extensively surviving system of Civil War and later defences on Scilly by giving advanced warning of approaching danger and allowing preparation of the main system of defences which were necessarily sited at lower levels to permit effective and accurate gun fire with the technology available at the time. Nearby Civil War batteries include examples on the lower northern slope of Mount Todden and on Toll's Island, 70m and 440m to the NNE respectively. In 1792 the Admiralty surveyor Spence described the battery and lookout as an `old watch house', but in 1796, the Rev John Troutbeck recorded that the battery still retained one cannon, that the watch house was bomb-proof, and that in time of war three islanders and one soldier kept watch there every night.

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: 15472

Legacy System: RSM


Books and journals
Ashbee, P, Ancient Scilly, (1974)
Ashbee, P, Ancient Scilly, (1974)
O'Neil, BH St J, Ancient Monuments of the Isles of Scilly, (1949)
O'Neil, BH St J, Ancient Monuments of the Isles of Scilly, (1960)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Gerrard, S., English Heritage Book of Dartmoor, 1997, Forthcoming
Gerrard, S., English Heritage Book of Dartmoor, 1997, Forthcoming
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7434.01, (1988)
Rees, S E, AM7 scheduling documentation for CO 1019, Mount Todden battery, 1975,
Title: 1:2500 Ordnance Survey Map; SV 9211 Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Map; SV 9211 Source Date: 1980 Author: Publisher: Surveyor:
Title: 25": 1 mile Ordnance Survey Map showing Mount Todden area Source Date: 1908 Author: Publisher: Surveyor:

End of official listing