Monument MPM1095 - Amhurst Redoubt

An outlying defensive work which formed part of the late-18th century Portsea line of defences. The redoubt was demolished c1860s. Part of the stone foundations were revealed during a watching brief for an extension to the Nuffield Sports Hall in 2005.

The Amhurst Redoubt formed part of the late 18th century Portsea Line of defences, work on which began in the 1770s. An isolated defensive work, the redoubt stood as an island at the southeast end of the Mill Pond (which formed a moat) and could only be reached by a small foot bridge from Mill Dam Road. Its function was to cover the gap between the Portsmouth town defences and the Portsea Lines, where they were separated by the Mill Pond and Mill Dam. The design was similar to a ravelin, with features for frontal defence, but open at the rear. It was demolished in the 1860s and 1870s, along with the majority of the Portsmouth and Portsea defences. [1] [2]

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A watching brief carried out on the groundworks for the extension of the Nuffield Sports Hall in 2005 revealed part of the stone foundations of the Redoubt. Sports facility buildings, tennis courts and playing fields built in the 1930s and 1940s occupied part of the present site of the Nuffield Sports Hall prior to development in 2003 and 2005.

The remains of the Amhurst Redoubt were represented by a series of massive stone features revealed in the north-west corner of the site. A substantial linear stone foundation of limestone bonded with lime mortar, which had formed part of the base of the main north-east facing wall of the redoubt, was exposed. The south-west face of the foundation was straight, but behind this it had been robbed of stone and only survived to a width of 0.6m. At the southern end of the surviving stonework was a feature thought to be a robber trench caused by the removal of stone from the wall. Two reinforcements or low buttresses of similar construction to the wall extended south-westward from the centre and northern sections of the exposed foundation. To the south of these features were the remains of a probable third internal buttress. These features would have been buried beneath the earth platform (mound) which formed the main bulk of the Redoubt.

A layer of loose gravel and a silty clay overlaid the tops of the buttresses and truncated the demolished wall. This was interpreted as the remains of the earth mound. Where this layer overlaid the remains of the wall, it was interpreted as having resulted from the levelling of the earth mound following the demolition of the defences. A sherd of mid-late 19th century pottery and a fragment of roof tile were recovered from the layer.

Silty clay deposits may have represented an accumulation of alluvium (soil deposited by water), and were therefore probably related to the moat. A stony deposit may have been backfill, suggesting the moat had been filled in before the stone structure was demolished.

[2]

A watching brief carried out during the excavation of footings and foundations for the Nuffield Sports Hall in 2003 revealed no trace of the Amhurst Redoubt or any other archaeological features. [3]

<1> Patterson, B.H., 1987, A Military Heritage A History of Portsmouth & Portsea Town Fortifications (Bibliographic reference). SPM43.

<2> Cottrell, P R, 2006, An archaeological watching brief at the Nuffield Sports Hall, Cambridge Road, Portsmouth, Hants (Unpublished document). SPM113.

<3> Currie, C K, 2003, An archaeological watching brief at the proposed Nuffield Sports Hall, Cambridge Road, Portsmouth, Hants (Unpublished document). SPM112.