Coastal artillery defences on the Isle of Grain, immediately east and south east of Grain village


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Scheduled Monument
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Ordnance survey map of Coastal artillery defences on the Isle of Grain, immediately east and south east of Grain village
© Crown Copyright and database right 2019. All rights reserved. Ordnance Survey Licence number 100024900.
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The building or site itself may lie within the boundary of more than one authority.

Medway (Unitary Authority)
Isle of Grain
National Park:
National Grid Reference:
TQ 88972 76405, TQ 89077 76559, TQ 89193 76555, TQ 89231 75655, TQ 89261 76119, TQ 89642 76043

Reasons for Designation

As a maritime nation, Britain has traditionally relied upon her navy for coastal defence, until the rise of air power after World War I. To support the navy, a system of fixed artillery positions were constructed at strategic coastal locations to protect important anchorages and ports from a seaborne attacker. Their construction coincides with periods of potential invasion and the anticipation of possible hostile raids. A range of coastal artillery defences are represented on the Isle of Grain, due to its strategically important position at the mouth of the River Medway, including artillery towers, Royal Commission fortifications and coastal batteries. Artillery towers are essentially raised gun positions of simple form and formed a consistent feature of artillery defence from the late Middle Ages to the introduction of anti-aircraft emplacements in World War II. The most extensive use of artillery towers was in the early 19th century when the specific group of martello towers was built to protect vulnerable points along the south eastern and eastern coastline, in response to the threat of a Napoleonic invasion. From a period spanning some 250 years of coastal fortification, isolated artillery towers, and their larger, low-level relatives known as redoubts, are rare nationally, with only about 17 surviving examples. All examples retaining a diversity of original components are therefore considered to merit protection. The Royal Commission fortifications are a group of related sites, established in response to the 1859 Royal Commission report on the defence of the United Kingdom. This was set up following an invasion scare caused by the strengthening of the French Navy. These fortifications represent the largest, and most expensive, programme of defence construction ever seen in Britain, until the major conflicts of the 20th century, and involved the improvement of existing fortifications as well as the construction of new ones. There were eventually some 78 forts and batteries in England, which were due wholly or in part to the Royal Commission, and most of these survive today. They constitute a well defined group with common design characteristics, armament and defensive provisions. Whether reused or not during the 20th century, they are the most substantial core of Britains coastal defence system, and most surviving examples are considered to be of national importance. Additional batteries were also constructed to provide supplementary fire-power for the existing Royal Commission fortifications during periods of potential invasion or hostile raids on the coastline, and existing forts were modified to carry improved ordnance. Wing Battery and Grain Battery belong to a group of about 23 surviving examples of batteries constructed during the period between 1895 and 1914, when standardised gun emplacements with integrated magazines and crew shelters were required for the new breech-loaders and quick-fire guns. Major technical innovations were also introduced at this time, including electrical and telephone systems, and batteries began to incorporate additional components, such as range finder positions, and command posts. Despite later modifications, the 19th century coastal defences on the Isle of Grain retain a significant proportion of their original features, providing information related to their construction and use. The subsequent remodelling of earlier features, and the additions made to the coastline during both World Wars, provide a rare insight into how military engineering and design was forced to adapt to meet the radical improvements to artillery and the changing character of naval warfare. The fortifications at Grain represent a major landscape feature which developed over a century of continuous military occupation, and the significance of the monument is further enhanced by its potential amenity value as an educational resource.


The monument, which falls into six separate areas of protection, includes five 19th century coastal artillery fortifications, including a gun tower, a fort and three batteries, and later 20th century additions, including two searchlight emplacements, constructed on low-lying ground on the eastern reaches of the Isle of Grain, commanding the entrance to the River Medway. They formed part of the wider Thames and Medway defences and, with the positions on the opposite side of the channel at Sheerness, provided a fixed, first line of defence to protect the important naval dockyards and commercial ports from a seaborne attack. Grain Tower was constructed in response to fears of a French invasion during the mid-19th century, and is located on a tidal mudflat which projects into the Medway channel. The three-storeyed, roughly oval artillery tower, is brick-built with walls faced in granite ashlar, and is Listed Grade II. Its design resembles that of the martello towers, built along the south and east coast of England in the early 19th century. A thick central column rises from the basement to the top of the tower, from which springs the barrel vaulted first floor ceiling which supports the gun position on the roof. The first floor doorway, the lintel of which is incised with the tower's completion date of 1855, is reached by boat at high tide or, originally, by steps at low tide approached from the shore by a causeway of concrete block and timber construction. Cartographic evidence suggests that the causeway was moved from its original north west to south east alignment to its present east-west position by 1889. The first floor provided accommodation for the garrison, with ammunition and supplies stored in the basement below. An internal staircase rises from first floor level to the gun platform on the roof, designed to carry one 56-pounder and two 32-pounder cannon, mounted on traversing carriages behind an encircling parapet. In the years leading up to World War I, the tower became the western anchor point for a chain boom defence across the mouth of the Medway to Sheerness, and remains of the chain survive around the base of the tower. Remnants of the fixed, timber section which connected the tower to Grain beach, and extended beyond the tower towards the central channel, can also be seen at low tide. The roof of the tower was also remodelled to accommodate the emplacements and support structures for two 4.7in quick-firing (QF) guns, installed to cover the boom, and two new magazine chambers were inserted at first floor level. Much of the southern emplacement survived the further, radical alterations made to the roof during World War II. The tower was re-armed in 1940 with a twin 6-pounder QF gun, to deal with incursions by high-speed German torpedo boats, and a coastal artillery searchlight emplacement was added to the side of the tower to assist the gun during night attacks. Accompanying structures include a battery observation tower located on the roof behind the emplacement and a free-standing barrack block, constructed on stilts, with access from the tower on its north western side, providing extra accommodation for the wartime detachment. Many original features survive from this period, including the remains of an electrically powered cage lift, installed at first floor level to meet the gun's requirement for a rapid supply of ammunition. Grain Fort was added to the coastline during the 1860s, on the recommendation of the 1859 Royal Commission into the Defences of the United Kingdom Fortifications, to support Grain Tower and the defences at Sheerness. The fort consisted of a north-south aligned, semi-circular brick keep, enclosed on its eastern front by a ditch, and a large, heptagonal earthwork beyond, designed to support the armament. The western gorge wall of the keep extended to meet the ends of the rampart, and the compound was completely enclosed by a substantial outer ditch. The keep provided accommodation on two levels, for at least 250 men, and was arranged around a central parade. The parade was entered through a passageway in the gorge wall, defended by two demi-bastions and approached through a gap in the rampart. The keep was further protected by five caponniers constructed within the surrounding ditch. Subterranean passages led from two of these structures, beneath the rampart, to four caponniers in the outer ditch. The main magazine survives within the north eastern passage, and was surveyed in 1999. Many of its original fittings survive, including the remains of the ammunition lift and some of the notices labelling various components of the magazine. Subsidiary magazines, and ancillary chambers, were located beneath the terreplein, which was designed to support 13 heavy, rifled muzzle-loaders (RMLs) and was accessed, via a covered way, from the inner ditch. The armament underwent a series of upgrades before the final allocation of two 6.2in guns in World War II for close defence, and a spigot mortar at each end of the terreplein, traces of which survive. Grain Fort was decommissioned in 1956 and its appearance subsequently altered by the demolition of its keep, and the partial infilling of the surrounding ditch. In addition to this substantial Royal Commission fortification, a series of open batteries were constructed along the coastline to the south. The first was built in the 1860s, approximately 1km south of Grain Fort and, originally known as Grain Battery, was renamed Dummy Battery in 1901. The two positions were linked by a communications road which was carried on an earthen bank across marshland to the south of Smithfield Road. The bank survives as an earthwork, up to 2m high and 4m wide. Two small structures, built at the southern end of the bank during World War I, are thought to be related to the telephone system or power supply for the battery. On dryer ground to the north, the road was carried in a sunken way, protected by the bank on its seaward side. The north-south aligned Dummy Battery was defined by a J-shaped earthwork, enclosed by an outer ditch on its eastern front. The concrete core of the earthwork originally supported a linear arrangement of 11in RMLs. The weapons were upgraded to 6in breech-loaders in 1895, and these, in turn, were replaced by two 4.7in QF guns in about 1904-5, linked by a covered way, with an underlying magazine, and a battery control post to the south. The main magazine was protected beneath a large rectangular blast mound to the rear. The battery was abandoned after World War II, and subsequent earth moving during the 1950s exposed the concrete core and emplacements, and the ditch became flooded. The ancillary structures were also demolished at this time, and their floors can be traced on the ground behind the emplacements. Major advances in military technology during the late 19th century, led to the strengthening and modernisation of coastal defence, including the addition of two new batteries at Grain. The first, Wing Battery, was built immediately south of Grain Fort in 1895. It is defined by a north-south aligned, broadly lozenge-shaped bank, enclosing a central, rectangular hollow, entered at its southern end from the western gorge. The gorge is formed by the road running south to Dummy Battery. The gently sloping profile of the battery was designed to be almost invisible to a seaborne attacker, and its surrounding ditch contained an unclimable fence for added protection. It was equipped with two 11in RMLs and a pair of 4.7in QF guns, arranged in a line along the forward rampart, with magazines and detachment shelters below. The range finder positions were located on the rampart to the north and west, and the concrete remains of these survive. Several structures were added to the central hollow during World War I, but these were demolished, and the emplacements infilled, after the site was abandoned in 1956. Grain Battery was constructed to the west of Wing Battery in 1900, and remained in use until the 1930s. Its roughly rectangular, earthen mound was designed to carry a linear arrangement of four 6in breech-loaders on the terreplein. On its south western front the battery was enclosed by a ditch, which curves around the southern end of the earthwork, and contained an unclimable fence which extended to the rear. A slight outer bank was constructed along its seaward side, to help conceal the ditch from view. The battery was entered by a road from the north, which passed through a gate in the fence. It continued behind the forward rampart, providing access to the guns and their magazines, and to shelters constructed beneath the road. The support buildings for the detachment were located on its western side, and these were levelled, and the emplacements infilled, during the 1960s. The remains of two electric searchlight emplacements, installed before the outbreak of World War I, survive on the esplanade. Each consists of a small, rectangular, concrete chamber with an apsidal extension on the seaward side which housed the lights. The southern emplacement was extended to the rear by the addition of a small square room. There is now little trace of the complex system of anti-invasion defences, including machine gun emplacements and barbed wire entanglements, which were added to the coastline during both World Wars, although a strip of anti-tank obstacles survives along the beach to the north of the monument. A number of features within the area of the monument are excluded from the scheduling. These are as follows: the modern shed, situated behind the rampart of Grain battery; all modern fences, railings and gates; modern steps and benches; the surfaces of all modern paths and the surface of the modern esplanade, although the ground beneath all these features 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:
Legacy System:


Books and journals
RCHME, , Coastal Artillery Fortifications on the Isle of Grain, (1998)
NMR, 82/713, 0402, (1953)
NMR, OS/66228, 397, (1966)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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