Late 19th-early 20th century Woolpack Battery on The Garrison, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1014783

Date first listed: 28-May-1980

Date of most recent amendment: 01-Aug-1996


Ordnance survey map of Late 19th-early 20th century Woolpack Battery on The Garrison, 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 89798 10140


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.

The distinctive form of gun batteries developed at the end of the 19th century differed fundamentally from earlier batteries and provided the first application of principles that came to dominate the design of such defences in the 20th century. Their design and location reflects major developments in armament technology, strategic thought, the nature of the perceived threat and defensive policy. By the mid 1880s the development of an effective breech-loading system had considerably improved the speed of re-loading guns. Hydraulic and compressed air systems enabled the recoil of guns to be absorbed, allowing guns to be located on fixed centrally pivoted mountings which improved accuracy and speed of firing. Hydraulics were also deployed for ammunition supply from magazines. Lighter steel barrels and improved propellants gave greater muzzle velocities and range without requiring corresponding increases in gun size and weight, thereby increasing the manoeuvrability of the guns while the deployment of brass cartridge cases further increased the speed of re-loading. The invention of smokeless powder reduced the visibility of guns on firing. Coupled with these advances, the development of new range-finding equipment and electrical communications considerably increased the speed and accuracy of target position finding and the control and coordination of armament. These technological changes revolutionised the nature of field fortification considered appropriate to house the guns. Priority was given to open emplacements with fixed gun mountings and low profile earthwork fortifications which were hard to target while allowing the guns maximum manoeuvrability; defence against close quarters ground approach was provided by the newly- developed barbed wire entanglements in concealed ditches, reinforced by machine-gun and rifle fire across the unobstructed ramparts. The gun emplacements were served by underground magazines with hydraulic hoists. Early applications of these new principles of fortification were made in the later 1880s in the rather different context of infantry reboubts in south east England, their form characterised as the `Twydall Profile'. During the 1890s variants and developments of the Twydall Profile dominated new land fortifications for infantry and artillery, providing a major influence on the design of the defences constructed on the Isles of Scilly during its 1898-1906 phase of fortification.

The Woolpack Battery has survived well, preserving the original plan of both its earthwork and built structures with only very minor modification from reuse during World War II. Such intact survival of a battery from this phase is rare and of much importance for our knowledge of the development of modern artillery defences. Most other components in The Garrison's contemporary defensive system, which included this battery as a major integral part survive well. Spatially, the rare survival of such a complete defensive system allows the relationships of its components to be studied against their armament capabilities and the strategic methods by which those defences were intended to be used, in the controlled background of a single location. The system of defences to which this monument contributed was directly inspired by considerations of national defence; as such it also has a wider historical importance whose immediate context is defined by the national defence reviews which led to the implementation and later the abandonment of the naval base which this battery was designed to protect.


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


The monument includes a large gun battery situated behind the southern crest of the summit plateau of The Garrison, the south western promontory of St Mary's in the Isles of Scilly. The battery is one of two complementary gun batteries, with a barracks/caretakers quarters between them, built on The Garrison between 1898 and 1901 and forming part of a defensive system designed to protect a naval signalling and re-fuelling station then being established on the Isles of Scilly. The defences were operational until 1906 but the monument also includes minor structures from reuse of the site during World War II. The built and earthwork structures in this monument are also Listed Grade II. The listing extends to include the built structures of the battery's underground magazine and war shelter which are excluded from this scheduling, although the ground beneath and above is included. The battery's forward flank faces SSW, its field of fire commanding the deep water approach to the islands through St Mary's Sound. It has two concrete emplacements for 6-inch breech-loading (BL) MK VII calibre guns set into the rear of a rampart, behind which is a parade area called a terreplein. Beneath the emplacements are an underground brick-vaulted magazine and war shelter reached by a concrete-faced light-well. The terreplein contains a raised platform, called a traverse, containing a communications room and supporting the Battery Commander's Position and range-finding post. The emplacements, terreplein and magazine are contained within substantial earthwork defences comprising a forward rampart and a fully encircling outer ditch. The concrete gun emplacements are situated 25m apart in the rear of the rampart. Each emplacement includes a raised podium around a circular central recess which housed the central-pivot gun mounting. On its forward side, the podium merges into the wider, slightly higher, rear face of a broad concrete apron whose gently chamfered surface extends over the adjoining rampart top. The rear faces of the podium have cast-in metal brackets for handrail stanchions and contain recessed lockers to house shells and cartridges required for immediate use; the metal handrails and locker doors have not survived. Further lockers occur beside the podium in the adjoining rear face of the apron; shell and cartridge lifts from the underground magazine open at hatches in the rampart's concrete facing to each side of the podium. A concrete terrace extends back from the podium, ending at a sloping scarp down to the terreplein with access steps at each side. Beside the inner flank of each emplacement, concrete steps rise from the terreplein to the rampart crest. A flagstaff left of the ESE emplacement indicated when live firing was taking place. Between the emplacements is a deep rectangular lightwell, partly recessed into the rampart rear, with steps descending from each end to the battery's complex of underground structures which form that part of the Listed Building excluded from this scheduling. These comprise a brick-vaulted magazine with two cartridge stores and three shell stores, and a war shelter. These structures retain their original plan, though most original internal fittings, doors and joinery have been removed from areas still accessible. The SSW wall of the lightwell bears a concrete date-slab inscribed `1900'. Behind the emplacements and lightwell is the rectangular levelled terreplein, c.55m long, extending c.15m back from the rear of the rampart and defined to the sides and rear by a wall. Behind the lightwell it is paved to waterproof the underground structures beneath and drains led out beneath the outer defences from each end of the terreplein. The battery entrance is near the eastern end of the terreplein rear, now visible as an open gap but formerly closed by double armoured steel gates with loopholes. The gates opened outwards, borne on rollers engaged in surviving curved rails. Within the terreplein, the concrete-revetted semicircular traverse extends from the centre of the rear wall; it contains a small communications room accessed from behind the traverse. The traverse platform supports a concrete parapet covering the Battery Commander's Position. Above the communications room and parapet is a slender concrete post which formerly supported Watkin's depression range-finder (DRF) sighting equipment. The DRF at this monument was calibrated by sighting onto a datum post on the Cow Rock north of St Agnes. Close to the east of the DRF post, a small raised concrete structure contains a recessed locker in its rear face to house charts and an electric telegraph for recording and transmitting DRF data to the gunners. In the south west corner of the terreplein, against the rampart rear, is a small latrine. The battery's emplacements, magazine and terreplein structures are built within extensive low profile earthworks to protect them from incoming fire and ground approach. The earthworks include a forward rampart which, with the battery's other structures, is contained within a subrectangular ditch. The rampart reaches its crest between the gun emplacements, from where it slopes gently down, extending the profile of the natural slope beyond the ditch. Where it meets the ditch, the rampart measures 65m WNW-ESE by up to 21m wide and rises to 3m above the parade level at the gun emplacements. The broad subrectangular ditch extends around the outer edges of the rampart and the sides and rear of the terreplein to protect all of the battery's operational structures from ground approach. The ditch is flat-bottomed, 7.3m wide at the base, ranges from 15m-25m wide at the lip and measures 108m WNW-ESE by up to 78m NNE-SSW externally. It is interrupted only at the north east corner, at the entrance, and was designed to be filled with barbed wire entanglements secured by retaining spikes. The low profile of its earthworks rendered the battery more difficult to locate and target for enemy gunners and masked both ditch and emplacements from external view while allowing an unobstructed and wide field of fire for the guns. The Garrison's commanding position made it the focus for successive phases of fortification on Scilly from the later 16th century. In the 1890s, a joint army and navy review of the nation's coastal defences proposed the Isles of Scilly should become an advanced naval signalling and re-fuelling station, to be classed as a defended port, in view of their strategic position against perceived threats from French Atlantic naval bases. Implementation of these proposals between 1898 and 1901 produced two complementary gun batteries, this monument and the Steval Battery 125m to the north west, to cover the deep water approach to the islands and served by a barracks/caretaker's block between them. Records indicate that the batteries' magazines held 500 rounds per gun. The battery and the barracks defences reflect the latest fortification designs and technology available at the time. By 1902, the 6-inch guns of these batteries were felt to give inadequate defence against motor torpedo boat attack; a proposed third 6-inch gun battery was abandoned in favour of two 12-pounder quick-firing gun batteries, one above Steval Point, 275m north west of this monument, the other at Bant's Carn on the north western coast of St Mary's. Other structures of the defensive system in which this monument operated include coastal searchlight emplacements and their control posts at Woolpack and Steval Points, with their electricity supply generator housed in an 18th century battery between them. An artificer's workshop for the maintenance of the batteries' guns and mountings survives near the summit of The Garrison, 140m north east of this monument. During construction of these defences, national defence policy underwent a radical shift. German power replaced that of France as the dominant threat, a re-orientation strengthened by the signing of the Entente Cordiale in 1904. In the resulting re-alignment of the nation's defences to the east, detailed in the Owen Report of 1905, the Isles of Scilly were abandoned as a naval station and, with little commercial importance, they also lost their defended port status. Consequently, though these batteries had been used for coastal defence training, their guns were dismantled in 1906 and by 1910 had been removed for storage in Falmouth. During World War II, The Garrison housed a radar cell and aviation fuel stores. A homing beacon was installed on the Woolpack Battery to guide anti- submarine aircraft returning from patrol to airfields in south west England. It is in this regard that two raised concrete mast bases were added, one on each apron of the emplacements. Each mast base is visible as a raised cross with an enlarged square centre and transverse terminals. The beacon was powered by electricity generated initially by two Ford engines in the battery's underground complex, later replaced by mains cables brought to the battery. One of the magazine's cartridge or shell stores was also used as a barracks for Royal Canadian Air Force personnel. The battery's underground complex was also used to store aviation spirit after bombing raids in 1940 threatened its former location on Hughtown Pier. The battery's undergound complex, comprising its magazine, war shelter and lockers, are excluded from the scheduling but the ground beneath and above them is included. All modern signs, fittings, service trenches and their contents, and dumped debris are excluded from the scheduling but the ground beneath them is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.


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

Legacy System number: 15436

Legacy System: RSM


Books and journals
Saunders, A D, Fortress Britain, (1989)
Saunders, A D, Fortress Britain, (1989)
Stevenson, I V, Some West Country Defences, (1989), 11-26
1901-2; now in Public Record Office, Edwards, H, Measured plans and sections made on completion of battery, (1901)
Entry 1358-0/3/89, DNH, List of Buildings of Special Architectural or Historic Interest, (1992)
Entry 1358-0/3/89, DNH, List of Buildings of Special Architectural or Historic Interest, (1992)
Information given to MPPA by phone from Dick Linzey, 1/9/1995,
Keystone Historic Buildings Consultants, Star Castle, St Mary's, Isles of Scilly, 1993, Unpublished report for EH
Letter dated 3/11/1993, J Guy, Fortress Study Group, Letter to J Ratcliffe, CAU, re Scilly defences 1902-1910, (1993)
Letter dated 3/11/1993, J Guy, Fortress Study Group, Letter to J Ratcliffe, CAU, re Scilly defences, 1902-1910, (1993)
Notes ref to J P Osborne's diaries, Parkes, C/CAU, Scilly SMR entry for PRN 7908.06, (1994)
Parkes, C/CAU, Scilly SMR entry for PRN 7903.07, (1994)
Parkes, C/CAU, Scilly SMR entry for PRN 7908, (1994)
Parkes, C/CAU, Scilly SMR entry for PRN 7908.06, (1994)
Parkes, C/CAU, Scilly SMR entry for PRN 7909, (1994)
Report for Cons SW, Feb 1994, Linzey, R and EH Architecture Branch, Recs for Incr Statutory Protectn to Woolpack & Steval Batteries, Cons SW, (1994)
Title: 1:25000 Ordnance Survey Outdoor Leisure Map, No. 25: Isles of Scilly Source Date: 1982 Author: Publisher: Surveyor:

End of official listing