Early 20th century gun battery 150m north of St Mawes Castle


Heritage Category: Scheduled Monument

List Entry Number: 1013808

Date first listed: 09-Oct-1981

Date of most recent amendment: 10-Jul-1996


Ordnance survey map of Early 20th century gun battery 150m north of St Mawes Castle
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The building or site itself may lie within the boundary of more than one authority.

District: Cornwall (Unitary Authority)

Parish: St. Just-in-Roseland

National Grid Reference: SW 84036 32871, SW 84103 32907, SW 84109 32839


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

Reasons for Designation

The distinctive form of coastal defence batteries developed at the end of the 19th century differed fundamentally from earlier batteries and provided the first application of design principles that characterised such defences until the abolition of coastal artillery in 1956.

Their design and location reflects major developments in armament technology, the nature of the perceived threat and defensive policy. Until the 1890s, heavy carriage-mounted guns recoiled up an inclined plane, and the gun's movement across a horizontal plane was provided by mounting the incline on rails. The gun crew had to keep well back from the gun during firing and return to the gun to re-load it from the muzzle before returning it to its firing position, slowing the rate of fire. By 1885, an effective breech- loading system improved the speed of re-loading, but the major advances came later with the development of guns whose recoil was absorbed by hydraulics and compressed air. Hydraulics were also deployed for ammunition supply from magazines. Lighter steel gun barrels and improved propellants allowed greater muzzle velocities and increased range without requiring the guns to have an enormous size and weight, while brass cartridge cases enabled more rapid re- loading.

By the end of the 19th century these developments allowed batteries to mount light, powerful guns fixed on a central pivot, enormously improving the guns' manoeuvrability and accuracy, and enabling rapid fire with the gun crew remaining close around the gun, protected from bullets and shrapnel by a gun-mounted shield. The new batteries reflecting this advance had fixed guns on steel mountings set in concrete emplacements, slightly sunken behind a concrete apron and protected from artillery fire by an earthen rampart. They were served by brick-vaulted magazines built deep underground, linked to small ammunition stores called expense magazines at the emplacements by hydraulically-operated shell and cartridge hoists. The underground magazines had an access well behind the emplacements.

The stimulus for implementing these major improvements in coastal batteries from the 1890s arose from a shift in British defence policy away from large land defences around major towns and military centres to counter threats from an invading army and towards coastal defences to counter the threat to naval and commercial ports and anchorages from the new generations of more manoeuvrable enemy cruisers and particularly from fast motor torpedo boats. The resulting new design of batteries were initially deployed along strategic points of the south coast and around major coastal centres elsewhere, when France was perceived as the main potential enemy. During the 1900s, the emphasis shifted to increasing the fortification of the east coast as Germany became viewed as the chief threat. This occasioned the scaling down and closure of some south coast batteries, a trend confirmed by the Owen Report of 1905 which substantially downgraded the extent of the perceived threat to many anchorages and therefore the strength of batteries needed to protect them. This produced the pattern of coastal defences prevailing at the start of the First World War and marks the end of this distinctive phase of policy and design in the nation's overall defences.

This battery at St Mawes shows well the new design features which were used during this short-lived but important phase of coastal defence and it remains little modified by later activity. Its replacement of the slightly earlier and inadequate 6 pounder battery near the shoreline emphasises the formative stage that it represents in the deployment of the new armament. Its inter-dependence with the submarine minefield is emphasised by the intact survival of the minefield's control cell and the sighting post sockets. The well documented history of this battery's construction, armament and decline during the first decade of the 20th century closely reflects the known shifts in national policy through that period. Its proximity to the Henrician castle and the successive gun batteries on the headland from the 17th century onwards demonstrates well the developing nature of gun batteries and the armament and strategic methods they represent throughout the post-medieval period. This is set in its wider context by the monument's association with the surviving and complementary defences at Pendennis and, for later periods, St Anthony's Head.


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


The monument, which falls into three separate areas, includes an early 20th century gun battery at St Mawes, situated on the upper slope of a broad headland flanking the east side of the Carrick Roads, the mouth of the River Fal, on the south coast of Cornwall. This monument is contained within a wider area in the care of the Secretary of State. The gun battery was built between 1900 and 1904. It contains four gun emplacements protected by an earthen rampart and served by an underground magazine whose access-well is cut into a levelled stance behind the rampart. Two observation posts, for minefield control and position finding, are located within the monument to the north west of the gun emplacements and the battery caretaker's house and access route are situated south east of the emplacements. On the hillslope below the battery are two sockets which held sighting posts for use in seeding mines along submarine minefield alignments laid across the Carrick Roads. The battery's earthen rampart extends over 70m north west-south east, rising steeply from the hill's upper slope and topped by a narrow level platform in front of the gun emplacements. The emplacements themselves each comprise a raised concrete platform into whose forward sector is set the circular steel gun-mounting with projecting securement studs around its periphery, called a hold fast. A short flight of steps rises up one side of the platform and in its rear face are two rectangular recesses called expense lockers, which stored ammunition for the gun's immediate use and which are closed by paired hinged steel doors, most of which survive in place. The forward edge of each gun platform is protected by a broad raised concrete apron set into the rear of the rampart and whose upper surface is chamfered outwards at a shallow angle. The rear face of an apron on the north eastern of the central emplacements has two metal loops supporting a vertical post, called an anti- strafing post, which acted as a stop to prevent the gun traversing too far east and firing on the artillery castle by accident. The north western three emplacements are spaced 7m apart, each pair linked by a low concrete catwalk behind a vertical rampart-facing wall into which are set two more ammunition storage recesses. The south eastern gun emplacement is 12m from the others and separated from them by a turfed rear scarp of the rampart.

Behind the gun emplacements is an area, c.7m wide, levelled into the hillside and backed by a steep scarp containing a further small storage recess near the centre. Within the levelled area and behind the south eastern two emplacements is the access well to the underground magazine.

The magazine's access well measures c.12m long by 2.5m wide, with concrete- faced sides descending vertically c.4m to the concrete floor. Its upper edge retains its original tubular railings, while above opposite corners along the south west side project curved tubular stanchions called davits, which were fitted with pulleys at their tips and which could swivel on their mountings. The davits were used for lowering ammunition supplies into the magazine. A steel flight of steps giving access to the floor have not survived.

From the floor of the well, an arched doorway in the south west side contains a double-door opening to the brick-built interior of the magazine proper. From this door, access was gained to the shell store and, with the addition of a further two emplacements to the 1900 battery in 1902-4 the magazine arrangements were altered to store more cartridges. The cartridge store was originally entered through another door from the lightwell (now blocked) directly into a shifting lobby. The north west wall of the lobby was demolished to enlarge the cartridge store and a new door created through to gain access from the shell store to the cartridge stores. The shell store retains its original racking and an arched window to the right of the door has its original grille. On the north east side of the access well, a doorway gives access to brick-built war shelter accommodation for the battery's detachment of troops. The doorway is flanked by two windows to its left and one to its right, all with concrete lintels and sills. The right-hand window retains its original grille; the other windows show no fittings for mounting such a grille. A lamp room with a door and window also extends from the north west end of the access well. On each long side, two ventilator pipes emerge from the upper walling and rise vertically, some showing parts of their internal fans in their upper end.

Close to the north west of the battery are two small observation posts, 8m apart north west-south east and largely concealed in a slight rampart whose forward edge is set back slightly from that of the battery. Both have concrete walls and are reached by a flight of steps descending to the rear of a semi- ovoid chamber, c.2.5m wide. The south eastern post served as a minefield control cell for the submarine minefield in the Carrick Roads; it has galvanised corrugated steel sheeting as its rear `wall' and a thick steel sheet forming its roof, beneath which is a narrow horizontal observation slit in the wall's front curve. The slit has been blocked by concrete but retains its wooden frame on the inner face, and a little way below this, granite slabs, called corbels, project inwards from the sides to support the position- finding table and its sighting equipment. The north western post was a position-finding cell for the battery and is more strongly built, with a concrete rear wall and a concrete roof on which is bolted a tubular steel pipe. The forward end of this post is angular rather than curved and has remnants of iron sheeting lining its observation slit. Beneath the slit, the now missing position finding table and sighting gear was supported on a corbel projecting in from the front wall and on two free standing concrete plinths behind the slit. The rear wall of this post retains its wooden door frame. The access route into the battery is along a partly-metalled terrace extending 25m east from the levelled area behind the gun emplacements and linking with the public road running down the slope. To the south of the terraced access route is a subrectangular levelled stance, 20m wide by up to 25m long, containing the accommodation for the battery's caretaker, together with a separate brick-built privy.

The hillslope below the battery contains two small sockets set on two of the alignments of mines in the post-1896 submarine minefield laid across the Carrick Roads and operated from the control cell next to the battery. The sockets held sighting posts inserted when mines were being seeded on the alignments. These sockets are situated 80m apart on a WNW-ESE axis; each survives with a concrete casing, 0.5m square in plan, with its level upper surface set almost flush with ground level. Within the casing is a cast iron lining, 4cm thick, around the socket, 16.5cm in diameter. The WNW socket remains open to a depth of 0.58m; the ESE socket is infilled with soil. Their original covers have not survived in situ but one is preserved in the contemporary engine room beside the Henrician artillery castle.

The construction, use and wider context of this battery are documented by a range of contemporary sources. From the 1890s, the defences at St Mawes, Falmouth and St Anthony's Head, were administered as a single defended port to protect the anchorage in the Carrick Roads and the port of Falmouth against enemy cruisers and, especially, the new fast motor torpedo boats. The initial defences in this phase at St Mawes involved, by 1898, mounting two 6 pounder quick-firing (QF) guns on an earlier battery near the shoreline, below the Henrician castle to the south of this monument. These were designed to complement the submarine minefield laid out across the Carrick Roads by c.1896 but those guns were soon found to be inadequate for their purpose and in June 1900, authorisation was made to build the first part of the battery in this monument, deploying the more powerful 12 pounder QF guns, mounted at a higher elevation giving a greater range. In this initial construction, completed by July 1901, the battery consisted of the two south eastern gun emplacements and the underground magazine behind them. The battery was substantially enlarged and its complement of guns doubled in a second phase of construction, between March 1903 and November 1904, when the two north western gun emplacements were added, together with their connecting catwalks. This phase also included the building of the two small observation posts to the north west of the battery, the caretaker's house to the south east and, beyond this monument, a searchlight station on the coast and an engine room to power it, situated north west of the Henrician castle.

Following a further review in 1905, the Owen Report, the defences of Falmouth were considerably scaled down. This resulted in an order to reduce the strength of this battery in 1906, followed by its closure in 1910. During World War II, the St Mawes headland was fortified from 1941 by a battery on the coastal margin south west of this monument, together with a minefield control post on the hillslope to the west. Although the battery in this monument was not re-armed, a range hut, now demolished, was built on the levelled area north west of the earlier magazine's access well.

The dwelling house which was formerly the battery caretaker's house, all modern fences, gates, garden furniture and sheds, the overhead electricity supply cables and their posts and fittings, and the roadsign with its post and pit 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: 15421

Legacy System: RSM


Books and journals
Dorman, J, The Later Defences of Falmouth 1895-1956, (1993)
Heggie, A V, Lane, M, Delta Graphics, , St Anthony Battery
Morley, B, The Castles of Pendennis and St Mawes, (1988)
Stevenson, I V, Some West Country Defences, (1989), 11-26
Tosh, D, St Mawes Castle A Brief Guide, (1993)
by letter, 18/3/1995, Information from Dick Linzey, EH Architecture & Survey Branch,
DoE/HBMC, AM Terrier and GAM mapping for CO 278: St Mawes Castle, (1984)
Linzey, R, Pendennis Castle. Obs & Hist Notes to accompany condition survey, 1995, EH report, February 1995
Title: 1:10000 Ordnance Survey Map: SW 83 SW Source Date: Author: Publisher: Surveyor:

End of official listing