Details

The monument includes standing, earthwork and associated buried remains of the
functional core of a World War II Heavy Anti-aircraft (HAA) gunsite. In
official records this was initially known as Humber F1 and then after 1st
August 1941 as Humber H27.
The monument retains a complex range of well-preserved structures representing
two main phases of development at the gunsite. RAF aerial photographs taken in
March 1941, August 1942 and December 1945 help to explain the evolution of the
site. Initially the gunsite had just two gun emplacements and an unroofed
command post. By August 1942, three more gun emplacements had been added
together with a new and larger command post
In February 1940, Humber H1 was one of 15 HAA gunsites established to defend
the Humber. The Regimental War Diary for the 10th July 1940 noted that the
gunsite was manned by personnel from 221 and 286 Batteries as a training sub
unit for Non Commissioned Officers. On the 28th April 1941 the gunsite was in
control of 286 Battery 91 AA Regiment and received four 3.7in mobile guns.
Control passed to 173 Battery 62 AA Regiment in June 1941 and then to 270
Battery to `man two 4.5in guns' which were supplied on 2nd August 1941 and
first used against enemy aircraft on 1st September. On the 14th September it
was noted that the new gun emplacements were complete and two further 4.5in
guns were supplied three days later. On 22nd June 1942 the gunsite was still
armed with four 4.5in guns and was guided by a GL MkII radar set. The gunsite
is believed to have continued in active service until 10th January 1945. The
controlling unit at that time, 462 battery of the 133 AA Regiment, was then
redeployed to gunsite HD at Kilnsea. This was part of Operation Diver, the
response to the threat of the V1 flying bomb. Incidentally 133 AA Regiment was
one of the mixed sex regiments established from summer 1941, that used female
ATS personnel to operate radar and other equipment. Humber H27 was not finally
decommissioned until sometime after the war. In January 1946 it was confirmed
to be one of the 192 HAA gunsites in England to be retained as part of the
post-war Nucleus Force. This provision of anti-aircraft gunsites was further
reduced in scale in the following years and Station H27 was probably abandoned
by 1950 by which time only 78 gunsites were operational nationally. The
monument includes the core functional structures of the gunsite along with the
linking concrete and hardcore road and trackways. The concrete access road
extends westwards from the lane and still retains some patches of tarmac skim
which was originally applied as camouflage. This runs into a turning circle
marked on the 1:10 000 map and surrounds the earlier command post which is a
concrete and brick structure 12m east-west and 5m north-south, with three
linked, slightly raised platforms surrounded by low parapet walls. From these
platforms, optical devices for determining identification, range and height of
aircraft were employed and orders relayed to the gunners. To the south is the
original pair of gun emplacements, which unlike the command post, are marked
on the 1:10 000 map. These are of a general design first issued in 1938. Each
emplacement is approximately 12m across and octagonal in plan, defined by a
blast wall. Set centrally into the concrete floor there is a ring for holding
down bolts for the gun mounting and extending inwards from six sides of the
blast wall there are six 2 sq m ammunition lockers. The remaining two sides
of the blast wall form wide entrances set on opposite sides of the emplacement
originally blocked by iron blast doors. The eastern emplacement is of concrete
construction, the western is built in brick. The ammunition lockers in the
eastern emplacement had been modified by August 1942 and the emplacement is
thought to have been disarmed and put to some other use following the
construction of the new command post and additional emplacements. Also by this
time the western emplacement had acquired an external concrete roofed shelter.
This would have been a relaxed duty shelter for the gun crew. To the south of
the emplacements, linked by concrete roadway is a five bay magazine complete
with blast walls and earth banking. The magazine is approximately 10m by 3.5m,
built using reinforced concrete with a flat roof which follows a standard
design produced by the Air Ministry in February 1939. It has had some
modifications to convert it into stables, including the removal of two walls,
but it still retains its original doors and windows. The monument also
includes the protective earth banking on the south side of the magazine.
By 14th September 1941, Humber H27 had been expanded to take four HAA guns.
Three new emplacements had been constructed, which together with the western
of the earlier emplacements, formed an arc around the south side of a new
command post. These were all linked by hardcore trackways which now survive as
buried features. These later emplacements, which are all well-preserved,
follow a different design to the first two examples. They also have two
opposed entrances that line up with the command post, and each has six square
ammunition lockers. However, these lockers extend out through the blast wall
which outlines a gunpit that is dodecagon in plan 8m across, rather extending
inwards from an octagon shaped blast wall. Each emplacement also has a crew
shelter reached from the gun pit via a short passage through the blast wall.
All of these emplacements have flat concrete roofs to their lockers and
shelters with the remains of camouflaging tarmac skims. They also have
protective earth banking against the outside of the blast walls which is also
included in the monument. However, the two flanking emplacements are built in
brick whilst the central one of the three is constructed with breeze blocks.
The later command post is larger than the example to the east. It is some 15m
east-west by 11m north-south with viewing platforms on its southern side and a
suite of rooms along the southern side. The largest room was the plotting
room, with smaller rooms acting as offices. One room, added to the rear of the
building, housed the boiler that ran the post's central heating system. This
feature is indicative of the arrival of women from the ATS, as no central
heating was provided previously. The station's domestic accommodation lay just
to the north east of the gun emplacements, adjacent to the West Marsh Lane,
with the accommodation for ATS personnel being between the lane and the
railway. By 1945 this included around 40 buildings, typically timber hutting
or temporary Nissens, most of which have been cleared over the years. The two
timber huts and the one Nissen, the latter relocated since 1945, which still
survived in 2000 are not considered sustainable as part of the monument and
are thus not included. The gun store, a typical concrete structure adjacent to
the access road to the emplacements, has been modified for domestic use and is
thus also not included in the monument. One brick building and a handful of
smaller brick structures also survive in the area of the domestic camp, but
their scattered nature, later modifications and existing uses make their
inclusion within the monument inappropriate.
A number of features are excluded from the scheduling: these are all fences,
gates, water troughs, and timber structures; although the ground beneath all
these features is 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 220m east of West Marsh is a particularly
well-preserved example of a HAA site. Its importance is heightened by the
survival of two designs of command posts and emplacements demonstrating the
evolution of HAA sites during the war.

Source: Historic England