Details

The World War II Heavy Anti-aircraft gunsite, documented in wartime records as
`TN8 (Thames North) Northwick', is located in an area of low-lying pasture
within the westernmost peninsula of Canvey Island, bounded to the north by
East Haven Creek and to the south by Holehaven Creek. The monument lies in
three areas of protection. The first includes the gun emplacements, the
command post, the on-site magazine, gun store and the associated section of
the military service road. The second area includes the sewage disposal unit
which was related to the battery accommodation and is situated some 150m to
the east of the gun emplacements. The third area includes the pump house,
which stands 150m to the south of the disposal unit and served the facility.

TN8 was designed for the operation of four heavy Anti-aircraft guns, each
mounted within an octagonal, shoulder-high concrete emplacement. Three of
these enclosures still stand and the foundations of the fourth are thought to
survive buried beneath a slight mound. The emplacements are constructed to a
recognised design, known as the `March 1938 pattern', arranged in an arc with
the apex facing east towards the usual direction of incoming German aircraft.
The three standing emplacements each contain six internal recesses built into
the internal faces of the surrounding walls. The remaining sides of each
octagon were originally fitted with steel gates which could be opened to allow
the movement of guns. The on-site magazine bunker, a bomb-proof rectangular
building, lies between the two northernmost gun emplacements. A second
unroofed rectangular structure, the gunsite command post, occupies the central
position within the arc of gun emplacements, accompanied by the generator
building which housed the power supply for the guns and locational equipment.
The gun store, a concrete garage-like structure, lies some 50m south of the
emplacements, to the east of the service road and north of the accommodation
huts for the garrison. Eleven of these brick built huts remain in use as light
industrial premises. The huts and the related part of the service road are
not, therefore, included in the scheduling.

The pump house, a small brick built structure, lies some 10m to the east of
the barracks. This served the camp's sewage disposal unit, which consisted of
a separation tank and a cluster of small ancillary buildings lying alongside a
drainage channel some 130m to the north east.

War Office documents on gunsite TN8 indicate that the battery was operational
by 1940 and mounted three 4.5 inch guns in June of that year, manned by 171
battalion of the 6th Anti-aircraft Division.

Container units and other modern items overlying the gunsite are excluded from
the scheduling, although wartime structures and surfaces beneath items are
included.

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

Source: Historic England

Reasons for Scheduling

Although of comparatively recent date, 20th century military sites are
increasingly seen as historic survivals representing a defining episode in the
history of warfare and of the century in general; as such they merit careful
record and, in some cases, preservation. One of the more significant
developments in the evolution of warfare during this period was the emergence
of strategic bombing in World War II, and this significance was reflected by
the resources invested in defence, both in terms of personnel and the sites on
which they served. During the war, the number of people in Anti-aircraft
Command reached a peak of 274,900 men, additional to the women soldiers of the
ATS who served on gunsites from summer 1941, and the Home Guard who manned
many sites later in the war. A national survey of England's Anti-aircraft
provision, based on archive sources, has produced a detailed record of how
many sites there were, where they were and what they looked like. It is also
now known from a survey of aerial photographs how many of these survive.
Anti-aircraft gunsites divide into three main types: those for heavy guns
(HAA), light guns (LAA) and batteries for firing primitive unguided rockets
(so called ZAA sites). In addition to gunsites, decoy targets were employed to
deceive enemy bombers, while fighter command played a complementary and
significant role. Following the end of World War II, 192 HAA sites were
selected for post-war use as the Nucleus Force, which was finally closed in
1955.
The HAA sites contained big guns with the function of engaging high flying
strategic bombers, hence their location around the south and east coasts, and
close to large cities and industrial and military targets. Of all the
gunsites, these were the most substantially built. There were three main
types: those for static guns (mostly 4.5 and 3.7 inch); those for 3.7 inch
mobile guns; and sites accommodating 5.25 inch weapons. These were all
distinct in fabric, though they could all occupy the same position at
different dates, or simultaneously by accretion. As well as the four or eight
gun emplacements, with their holdfast mountings for the guns, components will
generally include operational buildings such as a command post, radar
structures including the radar platform, on-site magazines for storing reserve
ammunition, gun stores and generating huts, usually one of the standard Nissen
hut designs. Domestic sites were also a feature of HAA gunsites, with huts,
ablutions blocks, offices, stores and amenities drawn from a common pool of
approved structures. Sites were often also provided with structures for their
close defence; pillboxes are the most common survivals, though earthwork
emplacements were also present. The layout of HAA gunsites was distinctive,
but changed over time, for example to accommodate the introduction of radar
from December 1940, women soldiers from summer 1941, and eight gun layouts
from late 1942.
Nearly 1,000 gunsites were built during World War II, and less than 200 of
these have some remains surviving. However, at only around 60 sites are these
remains thought sufficient to provide an understanding of their original form
and function. This includes 30 of the 192 examples which continued in use
until 1955. Surviving examples are therefore sufficiently rare to suggest that
all 60 well preserved examples are of national importance.

The Heavy Anti-aircraft gunsite 380m east of Northwick Farm is one of the most
complete examples in the country. It retains not only the gun emplacements,
associated magazine and command post, but also an exceptional collection of
ancillary buildings, including some (the pump house and sewage unit) which
rarely survive. Considered together with all other variations of Heavy Anti-
aircraft gunsite design, TN8 is one of only nine sites to survive (in any
form) from an original wartime deployment of about 40 HAA positions across
Essex, a pattern designed to combat German bombers on route to London, the
Thames estuary and other military targets in the south east of England. In
addition, this gunsite is one of the few remaining examples of the `March 1938
pattern' and provides a valuable insight into the development of anti-aircraft
measures in the region. It is a significant, visible reminder of the nature of
home defence during World War II.

Source: Historic England

Sources

Books and journals
Dobinson, C S, Twentieth Century Fortifications in England: Volume 1, (1996), 469-72
Dobinson, C S, Twentieth Century Fortifications in England: Volume 1.4, (1996), 469-72
Nash, F, World War Two Heavy Anti-Aircraft Gun Sites in Essex, (1998)
Other
9 colour prints, Carter, PJ, Frames 27 to 35, (1999)
9 colour prints, Carter, PJ, Frames 27 to 35, (1999)
Aerofilms, 90-234 Run 84 7053, (1990)
Black and white vertical, Aerofilms, 90-234 Run 84 7053, (1990)
Colour prints, Carter, PJ, Frames 27 to 35, (1999)
HQ 6th AA Division Location List, (1940)
HQ 6th AA Division Location List, (1940)
HQ, 6th Div., Location List HQ, 6th Div., (1940)
RAF, Run 38-020, (1960)
Tyler, S, MPP Film 7, (1999)
Vertical black and white, Aerofilms, Aerofilms 90-234 Run 84 7053, (1990)
Vertical black and white, RAF, Run 38-020, (1960)

Source: Historic England