Details

The monument includes the main compound, caretakers' cottages and external
stores of the North Weald London mobilisation centre, a late Victorian and
Edwardian military store and mustering station situated on rising ground to
the east of North Weald Bassett (within the grounds of the former Ongar Radio
Station), and known variously as the Essex or North Weald Redoubt.

The main compound is broadly `D'-shaped in plan. A 15m wide, semi-circular
ditch defines the north eastern `front' of the installation and a straight
channel, some 180m in length, completes the rear of the circuit to the south
west. The rear channel, known as `the gorge', contains a sunken roadway and a
row of reinforced concrete casemates which extend right along the northern
side. These, according to the War Office specifications of 1893, could be used
to accommodate 72 men. The majority of the chambers still retain half-inch
steel doors facing into the gorge, as well as wooden doors in the connecting
corridors and other internal fittings. The gorge is approached by two vehicle
ramps, one at the eastern end, the other descending the outer scarp from the
bridge which carries the principal access road across the gorge and onto the
reinforced roof of the casemates. The bridge, flanked by high walls and
massive cylindrical gate piers, overlies a caponier - a strongly-built
passageway linked to the casemates and pierced by loopholes to allow enfilade
rifle fire along the length of the gorge.

The approach road continues along the length of the casemates' roof, joining
two internal routes which lead northwards into the inner or `front' section of
the installation. This section includes a sunken semi-circular marshalling
yard, reached by shallow ramps and screened from the south by a massive
earthen blast wall. The northern side of the yard contains a curved row of
concrete casemates which carries the loop of the internal road across its roof
and is recessed behind a strong earthen rampart which matches the curvature of
the outer ditch.

The front casemates are well documented and the purpose of every chamber is
known. The row is divided into three main sections, one in the middle of the
curve and one at either end; the sections are separated by double fronted
rooms termed `gun casemates' (probably used for storing artillery pieces)
flanked by single chambers used as general artillery stores. Each of the three
main sections contains a `shifting lobby' (where protective and non-sparking
clothes were kept for magazine personnel), two cartridge stores joined by a
rear passage, and a separate shell store linked by an expense hatch. The shell
stores in the outer two sections also contained hoists leading to roof
apertures. The central section has a separate hoist chamber. The chambers
which were not used to store munitions are furnished with ventilation ports in
the ceiling and some also have windows facing into the yard. To minimise the
risk of explosion, however, the cartridge and shell stores were not ventilated
and the only light was provided by lamps set behind reinforced plate glass
windows and only accessible from the outer faces of the dividing walls.
Although the steel doors and shell hoists have been removed from the front
casemates, some of the original fittings survive. These include wooden
internal doors and expense hatch covers, lamp recess casements and some of the
original notices labelling various components of the magazines.

Although not essentially designed as a fort, the mobilisation centre did have
a defensive aspect and was certainly considered as a potential redoubt from
which to maintain resistance if adjacent sections of the defence line were
overrun. The earthen bank to the north of the front casemate, as well as
serving as a blast wall around the magazine, was also designed with the
potential for mounting a battery of six guns behind a series of projecting
bastions. Although the main guns were never installed, the casemates were
fitted with two forward passages, giving access to hollows in front of the
bastions which may have been intended as weapon pits. In addition to this, the
entire complex was surrounded by a wire fence set back from the ditch, and the
ditch itself contained tall spiked railings known as a dacoit fence. Both
these features have since been removed.

The North Weald Redoubt was not intended to be permanently garrisoned, but
provision was made for caretakers. Two uninhabited single-storey cottages,
brick-built with slate roofs, stand within the line of the original perimeter
fence, immediately to the south of the bridge. Both conform to standard
military designs of the period - that to the east of the access road dating
from 1890 (during the first stages of the centre's construction) and that to
the west added in 1893. Immediately to the east of the earlier cottage stands
a small square building of similar construction. This, although later used as
a boiler room, has been identified with a blanket store proposed in 1904. To
the east of this building are two rectangular halls, set in line, also
brick-built with rivetted iron trusses supporting a slate roof. These are
additional shell and cartridge stores documented on War Office plans dating
from 1904. They remain essentially discrete structures, largely unaltered and
intact despite their amalgamation with a later radio station workshop on the
south side (which is not included in the scheduling). Buried beneath ground
level to the east of the eastern store is a large water tank added in 1904 and
linked to an earlier concrete cistern set in the southern face of the gorge. A
similar cistern, designed to serve the needs of the front casemates, is
located on the southern side of the inner yard.

Construction of the North Weald Redoubt began shortly after the land was
purchased in 1889 and was largely completed by 1904. It was retained as a
military base in the decade leading up to 1914, and it is then thought to have
served as an arsenal for the duration of the Great War. In 1919 the site was
sold at auction to the Marconi Wireless Telegraph Company, who established a
radio station on the surrounding hillside (the last original radio mast from
this period was taken down in 1982) and used the redoubt for storage. The
Imperial and International Communication Company took over the site in 1929
and continued operations under the new name of Cable and Wireless after 1934.

The radio station came under direct government control during World War II
and this use, plus the site's proximity to the Southern Fighter Command base
at North Weald airfield, may explain the presence of an unusual form of World
War II gun emplacement, known as the `Allen-Williams' turret, situated on the
south eastern terminal of the rampart above the eastern approach to the gorge.
It consists of a rotating steel dome, 1.5m in diameter, set over a concrete
lined pit with an entrance passage to the west. The dome contains space for
two men, one to rotate the upper section, the other to operate the armament
(since removed) which could include the Bren or Lewis machine gun or the Boys
anti-tank rifle. The machine guns could be mounted through the square aperture
in the side of the turret or the circular opening above. It could thus be used
against both ground and aerial attack.
After the war in 1950, the radio station came under the control of the Post
Office and the redoubt was used and maintained by the GPO (and latterly
British Telecom) until the site was decommissioned in the early 1990s.

A number of features within the area of the monument are excluded from the
scheduling; these are the timber-built rigging workshop overlying the eastern
end of the gorge casemates, the brick-built workshop (most recently used as an
engine generator test centre) attached to the southern side of the 1904
cartridge and shell stores and the comparatively modern annexes attached to
the eastern end of the latter building, the comparatively modern garage
building within the inner courtyard, all modern oil tanks, their brick
supports and all modern vehicle inspection ramps, all modern fences,
fenceposts and gates surrounding the perimeter of the monument; however the
ground beneath these features is included in the scheduling, together with
the structures and surfaces related to the military use of the site, to which
some of these features are attached.

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

Source: Historic England

Reasons for Scheduling

The 15 London mobilisation centres, constructed during the 1890s, formed part
of a comprehensive military scheme known as the London Defence Positions,
drawn up in 1888 to protect the capital in the event of enemy invasion. The
scheme was a response to the rapid progress made in warship production by
France and Russia during the early 1880s, which had led to official doubts
about the Royal Navy's defence capability. Essentially a contingency plan, it
provided for the establishment of a 72 mile long, entrenched stop-line divided
into ten tactical sectors and supported by artillery batteries and redoubts.
The planned stop-line ran from the southern edge of the Surrey and Kent Downs,
up the western side of the Darenth Valley to the Thames, and then north
westwards through Essex from Tilbury Fort to Epping. Although the stop-line
and main defence positions were not to be established until an invasion was
imminent, it was thought prudent to build a series of mobilisation centres, 13
on new sites, along the projected course, either for artillery deployment or
where troops could assemble and collect tools and supplies. By 1905, official
confidence in the Royal Navy had been restored, and the now obsolete
mobilisation centres were abandoned and gradually sold off.
No two mobilisation centres are exactly alike, and a broad distinction can be
drawn between the four centres purpose built for artillery deployment, and
eight which functioned as infantry positions. However, in general terms there
are close similarities: each, for example, was typically enclosed by a
rampart, ditch and spiked fence, containing a partly earth-sheltered,
reinforced concrete and brick built magazine and stores. Beyond the main
compound were associated buildings of a standard type, including a brick
caretakers lodge and a large, barn-like tool store. Most mobilisation centres
have been the subject of subsequent alteration and/or reuse. As a short-lived
and rare monument type, all mobilisation centres with surviving remains
sufficient to give a clear impression of their original form and function are
considered to be nationally important.

The North Weald London Mobilisation centre, officially known as The North
Weald Redoubt exhibits a remarkable level of survival, no doubt largely as a
result of the sympathetic (or cost-effective) reuse of the site as a radio
station after the First World War. Not only do the earthworks and casemates of
the main compound remain substantially intact but, unusually for this type of
monument, the contemporary caretakers' cottages and external stores also
survive with few modifications when compared to the original War Office plans.
As with all more recent military installations, the operational use of the
centre is poorly recorded; these plans, however, provide clear documentary
evidence for the design and intended use of this, the most northerly of the
mobilisation centres within the ring of the London Defence Positions.
The Allen-Williams turret is a well preserved example of a comparatively rare
form of gun emplacement, a small number of which were produced in 1939-40 by a
company specialising in pre-fabricated building components. Unusually, it
still retains all the principal elements of its dual purpose design, and its
use in this location illustrates the renewed military significance of the
redoubt as a radio station during World War II.

Source: Historic England

Sources

Books and journals
Beane, A, A History of North Weald Bassett, (1884), 125,140
Sprack, P, Allen-Williams Steel Turret: Bembridge Fort, Isle of Wight., (1989)
Kent, P, 'Fortress' in East Anglian Fortifications in the Twentieth Century, , Vol. 3, (1989), 54
Smith, V, 'London Archaeologist' in The London Mobilisation Centres, , Vol. 2,10, (1975), 244-48
Other
AM107 site report, Chant, K, Essex Redoubt at the Ongar Radio Station, (1987)
copies at Imperial War, Duxford, War Office, North Weald Redoubt (WO 78 2404), (1892)
copies at Imperial War, Duxford, War Office, North Weald Redoubt (WO 78 2606), (1893)
copy at Imperial War Museum, Duxford, War Office, North Weald Redoubt Record Plan No.5, (1904)
discussions with Def of Brit officer, Samson, M, North Weald Redoubt, (1998)
info from Defence of Britain office., Samson, M, North Weald Airfield and the Battle of Britain, (1998)
supported by Defence of Britain Proj, Beard, P, North Weald Redoubt - draft discussion document, (1995)

Source: Historic England