Crownhill Fort


Heritage Category: Scheduled Monument

List Entry Number: 1020571

Date first listed: 19-Jan-1968

Date of most recent amendment: 02-Sep-2002


Ordnance survey map of Crownhill Fort
© Crown Copyright and database right 2018. 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.

District: City of Plymouth (Unitary Authority)

National Grid Reference: SX 48730 59276


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

Reasons for Designation

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 had been set up following an invasion scare caused by the strengthening of the French Navy. These fortifications represented the largest maritime defence programme since the initiative of Henry VIII in 1539-40. The programme built upon the defensive works already begun at Plymouth and elsewhere and recommended the improvement of existing fortifications as well as the construction of new ones. There were eventually some 70 forts and batteries in England which were due wholly or in part to the Royal Commission. These 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 visible core of Britain's coastal defence systems and are known colloquially as `Palmerston's follies'. All examples are considered of national importance.

Despite slight damage to its glacis, and late 20th century refurbishment, the Royal Commission Fort at Crownhill Fort is an outstanding example of its class and is accessible to the public. Its earth ramparts, walls and ditch, and outer glacis contain information about the fort's construction and use, while the gun emplacements and associated service buildings which lie upon and within the ramparts will contribute to an informed understanding of the site's development. The survival of numerous slit trenches and foxholes of World War II date provide evidence of the fort's later history.


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


This monument includes the earthwork, rock cut and some of the earth covered parts of a Royal Commission fort known as Crownhill Fort, built between 1863 and 1872 as part of a series of defences which protected the city of Plymouth and Devonport Dockyard from attack by land. Crownhill Fort was designed by Captain EF Du Cane as the principal and largest fort of the defensive line, and was set on a gently sloping hilltop 400m in advance of the main defensive lines. For this reason, its defences entirely encircle the site, which sits on the watershed between valleys running to the east and west, and also commands the main road into Plymouth from the north. The fort is as outstanding example of the later period Royal Commission fortifications and is the only one of Plymouth's such forts to be actively preserved and opened to the public. Crownhill Fort has an irregular septagonal plan and is accessed from the south via a single storey stone gatehouse with brick vaulted ceilings and bomb proof earth coverings. A Norman style granite outer arch, originally fronted by a drawbridge, gives access to a tunnel through the gatehouse, which could be defended as a keep with a second gate facing into the fort. Beyond the gatehouse, the access road passes through an open well with stairs accessing the rampart, before passing beneath the officers' quarters building and curving to the west up a sloping ramp onto a large level semicircular parade ground. Stone buildings of the 1870s-1890s surround this, some free standing, but most consisting of vaulted structures with bomb proof earth coverings. A single storey vaulted and earth covered range on the south side of the fort contained the officers' quarters. On the north side a similar, but two storied building contained the soldiers' barracks, with a vaulted and earth covered three bay magazine to its west. To the east of the barracks, a single storey cookhouse has a new roof of cast concrete construction. Other buildings to the east and west are free standing, with two long field gun sheds flanking the entrance to the south. A heavy earthen rampart measuring from 20m to 30m wide surrounds the fort, rising 8m from the interior. An intermittent firing step for infantry near its crest is interspersed with 16 gun positions of varying dates, mostly along the east and west sides of the ramparts, with a few along the north side. An open terreplain, possibly for use by moveable field guns but more likely for the assembly of infantry who would have manned the firing steps on the southern rampart, runs along the rear of the southern rampart. The fort was originally designed to contain 32 guns, including two sets of three 13 inch mortars in earthen pits on the west side of the fort, while four single and one double stone and brick built Haxo casemates with bomb proof earth roofs, which were finally armed in the 1880's with 7 inch Armstrong breech loading guns on traversing carriages which defended the south west, south east and eastern sides. The Haxo casemates were served by both overground expense magazines with bomb proof earth coverings, and vaulted underground magazines serving the casemates directly via hoists. These guns were supplemented in the 1870s and 1880s by open concrete emplacements containing three 64 pounder rifled muzzle loading guns; four Armstrong 7 inch guns mounted en barbette and two Moncrieff counterweight disappearing carriages mounting Armstrong 7 inch breech loading guns, located on the north west and north east angles. The guns mounted en barbette fired over low concrete parapets, while the Moncrieffs lay inside high walled semicircular emplacements. Ammunition recesses are cut into the rear of the rampart between the open air gun positions. Similar ammunition recesses are provided within the Haxo casemates. The outer face of the earth ramparts slopes gently at first, then drops steeply down to the top of a stone wall of dressed limestone and slate rubble which falls 9m into a rock cut ditch, measuring 7m wide at the top. The ditch sides batter in to a width of 5m at the flat bottom of the ditch. An open chemin des rondes, vaulted on the two northern faces of the fort to form covered rifle galleries, runs immediately inside the stone wall, with regular musket loops positioned to give a wide field of fire over a glacis outside the fort which falls away at an angle of 20 degrees until it strikes natural slopes. The glacis is therefore of variable width, measuring 250m from the outer edge of the ditch on the north west side, to 30m at the south east. The angles of the fort are defended by three storied stone faced demicaponiers with solid vaulted ceilings and bomb proof earth coverings. Each of these has musket loops on the upper and lower floors, and paired gun loops on the intermediate floors for 32 pounder smooth bore breech loading guns. Additional musket loops on three floors were provided in the re-entrant angles of each demicaponier, to cover the dead ground in front. All of these also contained sally ports at the intermediate level to allow infantry to enter the ditch. There are three demicaponiers on the east side and two on the west, those on the east facing clockwise and those on the west facing anticlockwise. The north angle of the fort has a trapezoidal full caponier located in a semicircular ditched projection from the ramparts. This contained two sets of the armaments found in the single caponiers, with additional musket loops and with a fifth gun position on the north side. This fired directly into a unique countermining gallery, served by two flights of stone steps leading down from the covered way on the outer side of the ditch. The gallery passes beneath the glacis and connects with the covered channels of Drake's and Devonport Leats, which curve around the hill on which the fort lies. Between the full caponier and the countermining gallery, the ditch widens to accommodate a single storey miniature caponier projecting onto the ditch floor This is rectangular, constructed of limestone ashlar with a solid stone hipped roof and three musket loops on either side, covering the outer angles of the full caponier. On the west side of the fort, the earth rampart angles back to form two triangular spaces behind the western caponiers. Sunken mortar pits here are accessed by tunnels beneath the ramparts from the fort interior and chemins des rondes and were each intended to contain three mortars. Outside the fort, a covered way for infantry runs along the outer edge of the ditch, with an earthwork firing step for rifle fire across the glacis. A number of features of World War I and II survive at the fort. Several gunports in the caponiers were infilled with brick to allow the mounting of machine guns to cover the ditches, while brick partitions in Drake's and Devonport leats assisted in the defence of these parts with machine guns. Several slit trenches were cut into the gently sloping outer face of the rampart and were accessed from the terreplain behind. These trenches vary in plan, but mostly run parallel to the ramparts with a central access to the rear. They are now lined with corrugated iron, fixed in place with angle iron posts, but were probably originally lined with timber. A number of foxholes of the same construction were placed on the firing step along the covered way outside the ditch. The drawbridge to the gatehouse was removed and replaced by an earth ramp, its sides sloping gently into the ditch on either side. Vehicles and equipment were stored here prior to the D Day Landings in 1944. The covered parts of the leats were used as an air raid shelter for Water Boar staff at the nearby water works. A set of 1880s metal fence posts flanking the entrance cutting are included within the scheduling, as are path surfacings on the ramparts and the floors of the gun emplacements. All free standing buildings, walls and road surfacings, all fence posts (apart from the 1880s metal fence posts flanking the entrance) and the originally earth covered buildings which have since had their earth coverings replaced (which include the officers' and soldiers' quarters) are excluded from the scheduling although the ground beneath these features is included. The buildings which remain earth covered are included within the scheduling.

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: 34881

Legacy System: RSM


Books and journals
Pye, A, Woodward, F, The Historic Defences of Plymouth, (1996), 175-178
Pye, A, Woodward, F, The Historic Defences of Plymouth, (1996), 175-178

End of official listing