Breakwater fort


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


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The building or site itself may lie within the boundary of more than one authority.

National Grid Reference:
SX 47161 50486


Royal Commission fortification known as Breakwater Fort.

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. As a result of sympathetic re-use the Royal Commission fortification known as Breakwater Fort survives well with many of its internal fixtures and fittings from various periods surviving. This is a unique monument being located behind the breakwater and not actually forming part of it. It is actually founded on Shovel Rock and is of particular importance because it had specific design, engineering and logistic requirements. Its continued importance throughout several other major conflicts indicates its strategic, military, historical and political significance through time.


See Details.


This record was the subject of a minor enhancement on 14 October 2015. This record has been generated from an "old county number" (OCN) scheduling record. These are monuments that were not reviewed under the Monuments Protection Programme and are some of our oldest designation records.

The monument includes a Royal Commission fortification known as Break Water Fort situated approximately 100m to the north of the centre of Plymouth Breakwater in Plymouth Sound and standing in some 15m depth of water. The fort survives as an oval structure of iron-framed concrete measuring approximately 48m long by 38m wide with a central courtyard. The foundations were built 10m below the mean sea level by divers. The gun decks on the upper floor and casements and magazines on the lower floor are protected by teak and iron armour sandwiched together. The iron walls of the casements are up to 1m thick. The exterior of the fort was originally painted in a black and yellow chequered pattern to disguise the position of the gun ports and some of the original paintwork survives. It was recommended in 1860 by the Royal Commission to close the gap between Picklecombe and Bovisand Batteries and thus protect any ships at anchor behind the breakwater. Originally designed to be a masonry four tier structure, tests proved that granite and masonry could not withstand the recoil from the guns, so a concrete and metal structure was devised. Work began in 1861 and the foundations were complete by 1865. The first gun was installed by 1879 and by 1880 the fort was fully armed with 24 guns of varying size although armaments changed through time. The 1860’s fort remains intact together with its internal fittings such as cartridge lifts, iron hose brackets and wooden shell shoes, gun pivots, rings and traversing rails. A searchlight was installed on the roof in 1902 and by 1905 more guns were placed either side of the entrance, but removed shortly after. During the First and Second World Wars it was the Port War Signal Station and there were positions for 18 guns with 11 casemates behind providing accommodation and these had fireplaces and cartridge lifts. Access to the magazine below was via spiral stairs of which one survives. Parts of the central coal storage bunker and water tank are now flooded. The diesel engines are still in-situ. The fort went out of military use in 1976.


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

Legacy System number:
PY 866
Legacy System:


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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