Monument MPM1757 - Long Curtain and Moat

Surviving section of curtain wall and moat belonging to the former fortifications that enclosed the town of Portsmouth until the mid-19th century. Long curtain wall/rampart originally dates to the late-16th century, and was remodelled during the late-17th century. The moat retains its late-17th century form.

Together with King's Bastion and Spur Redoubt, Long Curtain forms part of the only section of ramparts and moat which enclosed the town of Portsmouth to survive above ground. Long Curtain was the name given to the section of curtain wall/rampart which linked the Saluting Platform to the King's Bastion (see MPM1758). The present wall was originally constructed during the late-16th century and later remodelled by Sir Bernard de Gomme during the 1660s-1680s. It consists of an earthen rampart with an inclined inner face, flat top, stone outward face and brick parapet which boarders a walk way along the rampart. [1] The moats present form dates to de Gomme's late-17th century modifications.

A form of curtain wall/rampart had existed on the Long Curtain site from the late-14th century when the town was first enclosed by a simple earthwork and moat following a series of raids by the French [2]. A fortified wall with a crank half-way along is marked on an earlier 16th century map/plan, and this was replaced by a stone wall when the defences were remodelled by Popynjay in 1584 [3]. The curtain wall was modified again by Sir Bernard de Gomme during the 1660s-1680s. A tunnel was cut through the rampart (see below) and a bridge constructed across the moat to allow access to the newly built Spur Redoubt (MPM37) [2]. The earliest available map to suggest the existance of the tunnel is dated 1716 [7]. The moat was flooded by sea water via sluices located at the far end of the rampart [4].

The batteries on Long Curtain were upgraded and rearmed during the mid-late 19th century, at a time when the majority of the Portsmouth and Portsea line of defences were considered to have become redundant and were demolished. Long Curtain retained its importance due to the defensive position it commanded at the entrance to the harbour. In the 1890s one of the older gun emplacements was converted for use as an observation cell for a submarine minefield located in the entrance to the harbour. The mines would have been electrically triggered by the cell and a Submarine Mining Engine Room and Test Room situated behind it. The engine and test rooms were demolished in 1903 and the minefield became redundant in 1907. [4]

In 1903 two R.M.L. gun emplacements were removed and replaced by three 6pdr Q.F. emplacements. Two blocks of crew shelters replaced the Submarine Mining Engine Room and Test Room to the rear of the battery. The battery was completely redesigned in 1907-1908 with the construction of emplacements for four 12pdr Q.F. guns, three 6pdr Q.F. guns and two ammunition stores excavated underneath the emplacements. One of the 12pdr Q.F. gun emplacements constructed in 1907-08 survives almost intact, together with the concrete aprons of two others and the two eastern 6pdr emplacements. The ammunition stores and shelters have been removed. [4] The remains of the fourth 12pdr emplacement was probably destroyed during improvement works in 2005 (see MPM1867).

The full depth of the seaward wall of the Long Curtain moat and a short linking wall (MPM2142) were temporarily exposed during ground works for the Southsea Coastal Defence Scheme when an historic building recording was undertaken by Wessex Archaeology. The wall extended another 2m below what had been visible prior to a temporary reduction of the beach ground level during the works. This revealed original 17th century fabric in the lower courses of the wall which had been protected from beach scour and storm damage. Surviving details included intricately carved mason’s marks, thought to be those of individual quarrymen, etched into the stones. In contrast the upper courses of the wall that had been exposed to the elements contained evidence of several phases of repairs along it's length in a mixture of stone and brick materials. Repairs had been carried out to the core of the wall using concrete bags. [5, 6]

A sloped masonry surface/apron made from cobblestones which formerly covered the area of the beach between the Saluting Platform and Spur Redoubt was removed during the Southsea Coastal Defence Scheme works. The apron had extended up to a revetment wall built of large concrete blocks and a ramp walkway that followed the line of the Long Curtain seaward wall, covering the earlier structure. The apron, which acted as an earlier flood defence, had probably initially been laid during the early 19th century and was later extended. The feature is shown on a map of The Garrison Town of Portsmouth dated 1850. When the apron and revetment walls were removed the Long Curtain wall was found to be in poor condition and large sections had been replaced by footings to the Millenium Walkway. [6]


Sally Port Tunnel

An historic building recording of the Sally Port Tunnel was carried out by Wessex Archaeology prior to and during work to install a new flood gate in 2021 and 2022 as part of the Southsea Coastal Defence Scheme project. This concluded that most of the tunnel appeared to have been constructed in a single phase, but there was evidence of some repair/maintenance and a few alterations. This included patch repointing repairs to brickwork, repairs to a crack that extended down both walls and across the ceiling and a panel of concrete render added to the west wall that may indicate a remedial repair to the brickwork. Below is a summary of the results.

The tunnel is approximately 24m long and 1.5m wide and ranges between 1.96m and 2.01 in height. It is mainly lined with red brick and has a semi-circular barrel-vaulted ceiling. The north entrance is constructed from brick, possibly having been built in two phases. The Sally Port at the south end of the tunnel has been cut into the north side of the Long Curtain moat wall. The entrance chamber is constructed from ashlar limestone masonry and has a flagstone floor. Iron pintols used to hang an earlier door were observed inside a modern door frame on the east side. This modern doorframe was removed during the works. Fixing points for an earlier bridge structure were observed either side of the opening. The present bridge across Long Curtain Moat was constructed in early 21st Century in the same position as an original 17th century wooden bridge and is likely to be the latest in a succession of bridges in this position.

Both of the gates in the north and south entrance in existence at the time of the survey were modern replacements but remnant ironwork from earlier doors was observed in situ.

The floor of the tunnel was regraded with tarmac in 2004 and floor lights installed. The latter replaced electric wall lights, evidence of which was still present.

Two broken iron fixings were revealed behind cement render at the south end of the east wall of the tunnel. It is not known what function these would have performed.

[7]

<1> Historic England, The National Heritage List for England (Index). SPM35.

<2> Corney, A, 1973, Fortifications in Old Portsmouth - A Guide (Bibliographic reference). SPM388.

<3> Patterson, B.H., 1987, A Military Heritage A History of Portsmouth & Portsea Town Fortifications (Bibliographic reference). SPM43.

<4> Moore, David, 2013, Solent Papers No 12: Portsmouth Lines and Southsea Defences (Bibliographic reference). SPM497.

<5> Williams, Rachel & Tuck, Ashley, 2023, Southsea Coastal Defence Scheme Sub Frontage 1, Southsea, Hampshire: Archaeological Watching Brief (Unpublished document). SPM643.

<6> Flood, Grace, 2024, Southsea Coastal Defence Scheme Sub Frontage 1, Southsea, Hampshire: Historic Building Record (Unpublished document). SPM662.

<7> Flood, Grace, 2022, Southsea Coastal Scheme Sub Frontage 1 - Sally Port Tunnel Southsea, Hampshire: Historic Building Record (Unpublished document). SPM663.