Details

The monument includes Spitbank Fort, a circular 19th century Royal Commission
sea fort lying in the Solent on Spit Sand, 1100m south west of Southsea
Castle. Spitbank Fort was one of a chain of four sea forts in the Solent
recommended by the Royal Commission on the Defence of the United Kingdom in
1860, and designed to protect Portsmouth dockyard from seaborne attack.
Construction started in March 1867 and the fort was completed by June 1878.
The fort is circular in plan and includes sea bed foundation walls of 8 ton
pre-cast concrete blocks with an inner and outer casing of masonry. At the sea
bed the structure is 49.4m in overall diameter and the thickness of the
walls is 14.6m. The area enclosed by the circular walls is filled with
shingle capped with a slab of concrete 3m thick. Above this lies a basement
divided radially into compartments for ammunition and stores. The ammunition
stores were equipped with lifts to raise shells and cartridges to the guns on
the floor above. Above the basement the main floor supported the guns, for
which there are fifteen positions, six in granite fronted brick casemates on
the northern (landward) side of the fort and nine within an iron armoured gun
gallery facing out to sea. Within the centre of the fort, behind the casemates
and gun gallery, are the accommodation and ablutions for soldiers, sergeants
and officers.
Above this floor, the roof, which is reached by means of an iron staircase,
supports the battery observation post and lighthouse, the loading gantry, and
gun emplacements and other structures dating from the late 19th and early 20th
centuries.
The small building which is all that remains of the soldiers' latrine is
cantilevered out from the exterior of the fort.
The fort was armed with nine 12.5 inch 38 ton Rifled Muzzle Loader (RML) guns
on its armoured side and with 7 inch 7 ton RML guns facing landward. Most of
the RML guns were removed by 1898 when 4.7 inch Quick Firing (QF) guns were
mounted on the roof. The fort was armed during both World Wars, the last gun
being removed in 1948.
All modern security fittings, lighting, safety and catering equipment, signs
and all replica guns and introduced fittings and the replacement landing stage
are excluded from the scheduling, although the structures beneath are
included.

MAP EXTRACT
The site of the monument is shown on the attached map extract.

Source: Historic England

Reasons for Scheduling

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.

Spitbank Fort is a well preserved example of its class. As part of an
integrated sea based defensive line the massive structure of Spitbank also
provides a visual reminder of the strategic importance of the Solent in the
later 19th century.

Source: Historic England

Sources

Books and journals
Mitchell, G, 'Solent Papers no. 1' in Spit Bank And The Spithead Forts, (1986)

Source: Historic England