Details

The monument includes the upstanding and buried remains of a bunker
situated on the Otterburn Army Training Estate. The bunker, which served
as an observation post known as OP 9, is now redundant, and is one of a
group of four on the Training Estate situated in two pairs. The other
three bunkers and Ridlees Cairn are the subjects of separate schedulings.
The bunker was intended to provide shelter during training for parties of
16 Forward Observation Officers guiding artillery fire into the impact
area from mobile guns placed outside. The exact date of its construction
is uncertain but a similar structure, thought to provide a parallel for
the four Redesdale examples, was constructed on the Okehampton Artillery
Range in 1923/24. The bunker, which faces north to command views over the
Redesdale Impact Area, is visible as a rectangular blockhouse with
projecting triangular wings encased in an earth and stone mound. The
blockhouse is constructed of reinforced concrete and measures 23m long,
2.5m wide and it stands to about 2.1m above ground level at its front
face. The walls, which are splinterproof, are 0.45m thick. Four
rectangular recessed embrasures 0.46m deep and 2.1m wide pierce its front
face with a concrete lintel over, which projects 0.15m and is 0.5m high.
The mound, which encases the bunker, is 8.5m wide and about 1.75m high.
Its eastern end has been modified to form a ramped access to the roof. The
ramp extends for a further 7m beyond the rear of the earthen bank where it
is truncated by a vehicle turning circle.

Entry to the bunker is gained at the east end of the north face by a
series of descending concrete steps, which project, 3.5m from the front
face of the bunker. The stairway is protected on each side by a brick
blast wall, which gives access to an offset passageway about 0.8m wide.
Internally, the remains of a narrow wooden shelf that originally ran the
full length of the bunker immediately beneath the line of embrasures
survives at the east and west ends. Continuous raised wooden seating is
also present along the length of the bunker where the operatives would sit
to gain good vision. A drainage gully at floor level runs the length of
the bunker immediately below the embrasures. It passes through the east
wall of the bunker into a small drain within the offset passageway. The
concrete base and flue opening of a potbellied stove are retained in the
south west corner of the bunker and a field telephone is attached to the
west end of the north wall. Evidence of the corrugated iron shuttering
used in its construction is exhibited in the roof.

MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.

Source: Historic England

Reasons for Scheduling

The Army Training Estate Otterburn (ATEO) is one of seven Army Field
Training centres in the UK and is the largest single live firing area in
the country. It has been operational since 1911 when the War Office
acquired about 20,000 acres (8094ha) of land in Redesdale, Northumberland
to create a seasonal tented camp and artillery range for the training of
the newly formed Territorial Forces. The pattern of artillery firing from
Easter to October fitted in with local sheep farming practices, and
byelaws to control access during live firing periods were introduced in
1916. A period of intense training occurred during World War I to prepare
both artillery and infantry units for war, including the construction of a
sector of front line trenches at Silloans to practice infantry companies
in the routines of defence, control of overhead artillery fire and relief
in the line. After World War I the previous pattern of training was
restored and continued to 1939, the only change being that from horse
drawn to lorry drawn guns in 1938. During World War II, the training area
doubled in size with the acquisition and subsequent purchase of a further
20,000 acres (8094ha) to create a second Artillery Range and camp at
Otterburn. In 1959 the Ranges were renamed as an All Arms Training Area
and five infantry fire and manoeuver areas at Quickeningcote, Wilkwood,
Davyshiel, Sills and Heely Dodd were constructed under the Thurlow Plan.
From 1969 Otterburn was designated as one of seven Principal Training
Areas in the UK and became increasingly used for fire and manoeuver
training by infantry units supported by artillery, mortars, guided
missiles and air to ground attack aircraft. Developments since 1969 have
included the construction of another battle shooting area at Ridleeshope
and a moving target railway system at Stone in the Mire for engagement by
wire guided anti-tank missiles.

The observation post 140m north west of Ridlees Cairn survives well in an
unmodified state with a range of its component features intact. It was
constructed as one of a group of four bunkers, which represent a major
phase of artillery training between World Wars I and II. These are rare
examples of structures of this kind with the only parallel being single
examples at Salisbury Plain and Okehampton Training Areas. Hence they are
an important survival in the history of military training in England.

Source: Historic England

Sources

Other
Francis, Paul , (2002)
Thomas, Roger J C , (2002)

Source: Historic England