Monument MPM2146 - Remains of 17th century defences, Southsea Castle

Section of wall representing a former 17th century defensive structure observered during a watching brief for the Southsea Coastal defence Scheme. The structure was built in the c1680s as part of the remodelled defences to Southsea Castle designed by the military engineer Sir Bernard de Gomme.

Section of wall representing remains of 17th century defensive works formerly situated to the southeast of Southsea Castle and recorded during a watching brief for the Southsea Coastal Defence Scheme.

The wall was constructed from substantial irregular limestone blocks up to 1.05m long, 0.30m wide and 0.24m high, laid in random courses and bonded with a lime-based mortar. The surviving section of wall was 10.5m long, 4.5m wide and 3.0m high and is described as a 'curvilinear wall aligned triangular unit', west to east and north to south. The interior face of the wall was concave in profile, in contrast to the 90° angle of the seaward elevation.

The wall aligned with structures shown on a 1678 plan of upgraded defences to Southsea Castle designed by de Gomme. Sir Bernard de Gomme was Charles II's chief military engineer and was responsible for remodelling Portsmouth's defences during the 1660s-1680s. The wall formed the south facing projection of defences in the southeast corner of the Castle.

The southwest facing elevation of the 17th century wall was butted by a 19th century repair/replacement wall [see MPM2147]. The remains of the 17th and 19th century defensive structures have been preserved in situ and are protected by the new sea defences.

Williams, Rachel, 2025, Southsea Coastal Defence Scheme Sub-frontage 4, Southsea Castle, Southsea, Hampshire: Archaeological Watching Brief (Unpublished document). SPM671.