Reasons for Designation
Linear boundaries are substantial earthwork features comprising single or
multiple ditches and banks which may extend over distances varying between
less than 1km to over 10km. They survive as earthworks or as linear features
visible as cropmarks on aerial photographs or as a combination of both. The
evidence of excavation and study of associated monuments demonstrate that
their construction spans the millennium from the Middle Bronze Age, although
they may have been reused later.
The scale of many linear boundaries has been taken to indicate that they were
constructed by large social groups and were used to mark important boundaries
in the landscape; their impressive scale displaying the corporate prestige of
their builders. They would have been powerful symbols, often with religious
associations, used to define and order the territorial holdings of those
groups who constructed them. Linear earthworks are of considerable importance
for the analysis of settlement and land use in the Bronze Age; all well-
preserved examples will normally merit statutory protection.
The boundary known as the Buckinghamshire and Hertfordshire Grim's Ditch
includes numerous surviving sections from within three main linear earthworks
aligned along the Chiltern Hills between Bradenham and Berkhamsted, and
spanning a total distance of 18km. It does not appear that these principal
sections were ever joined to form a continuous boundary. Current evidence
suggests that the sometimes quite sizeable gaps represent areas which were
formerly forested or in which natural features served to perpetuate a division
of the land. The same pattern has been discerned along the North Oxfordshire
Grim's Ditch, to the west of the Thames. A further comparable linear boundary,
the Moel Ditch, extends to the east across parts of neighbouring Bedfordshire.
For the most part the visible sections of Grim's Ditch in the Chilterns
include a wide single ditch flanked by a bank of upcast earth, which is always
upslope of the ditch. Other features, discovered by limited excavations
include a turf core within the bank, a berm separating the bank and ditch
(concealed over time by the spread of bank material) and a trench for a
fence or palisade along the outer rim of the ditch.
The Buckinghamshire and Hertfordshire Grim's Ditch is thought to have served
as a territorial boundary, separating, and perhaps enclosing, organised groups
of land and settlement. It may also have been an agricultural boundary
denoting grazing and impeding the movement (or theft) of stock. Excavations to
date have only produced limited dating evidence. Pottery recovered from the
fill of the ditch indicates that it was in existence in the Iron Age. As such
the boundary provides important evidence for the management of the landscape
in the centuries preceding the Roman Conquest in AD 43, although it may have a
considerably earlier origin. It remained a notable feature in later centuries,
acquiring its present name (a variation on the name of the god, Odin) at
some time in the early medieval period, perhaps during the period of the
pagan Saxon settlement in the 5th and 6th centuries. The earliest recorded
use of the term `Grim's Ditch' occurs in a charter granted by Edward, Earl
of Cornwall in 1291.
All sections of the Buckinghamshire and Hertfordshire Grim's Ditch which
survive in visible form or as well-preserved buried remains (identified by
aerial photography or ground survey) are considered integral to a general
understanding of the monument and will normally merit statutory protection.
This section of Grim's Ditch to the west of Walter's Ash survives well as a
visible earthwork along most of its length and provides a fascinating insight
into early land division in the Chiltern Hills. It will contain archaeological
evidence for the manner of its construction as well as environmental evidence
for the appearance of the landscape in which it was built. The archaeological
evidence may also include artefacts or scientific dating material from which
to determine the period of its construction and the duration of its
maintenance as an active boundary.
The air raid shelters constructed alongside the prehistoric boundary during or
before World War II are now considered to be important historical features in
their own right. Air raid shelters of this type are more commonly associated
with active airfields of the period - part of the general development of
target dispersal, early warning systems and retalitatory anti-aircraft gun
sites. These shelters reflect the heightened danger of aerial attack facing
non-combatant staff and families due to the extreme strategic importance of
Bomber Command headquarters at RAF High Wycombe.
Details
The monument includes a 660m long section of a prehistoric boundary known as
the Buckinghamshire Grim's Ditch, located on high ground on the east side of
the Saunderton valley, running broadly north west to south east through Park
Wood and immediately to the west of the officer's mess at NATO Strike Command,
RAF High Wycombe.
This section of Grim's Ditch, in Park Wood to the west of Walter's Ash,
survives as a substantial earthwork along most of its length. The earthen
bank measures up to 13m wide and stands up to 1.4m high in some places. To
the east of the bank lies a parallel ditch, approximately 11m wide and up
to 1.2m in depth. Excavations along other sections of Grim's Ditch,
carried out in 1973 and 1991, produced evidence of a level area, or berm,
separating the bank and ditch. Evidence for a palisade trench, which would
have supported a wooden fence, were also found along the outer edge of the
ditch. Similar components may survive as buried features along this
particular section of the Grim's Ditch.
The southern 320m section of this length of Grim's Ditch lies within the
Officer's Mess and residential area of NATO Strike Command, RAF High
Wycombe. Despite some disturbance the monument is visible as a
well-preserved bank and ditch. Where the monument is no longer visible,
for example where it is overlain by the road to Bradenham Beeches, buried
remains of the bank and the infilled ditch are thought to survive. Within
this area are a number of air raid shelters associated with residential
housing for officers in World War II. Two of these air raid shelters were
built close to the western edge of the bank and are included in the
scheduling. They survive as oval shaped earthen mounds, measuring
approximately 8m long by 6m wide and approximately 1.5m high and sharing
the same alignment as the houses with which they are associated. The most
northern of the two mounds is orientated north west-south east and the
southern mound is orientated WNW-ESE. The entrances to the shelters have
been filled in and are no longer visible.
A further section of Grim's Ditch is visible 270m to the north, between
the headquarters of NATO Strike Command at RAF High Wycombe and Grymsdyke
Manor. This section and others along the the entire known route of the
boundary are the subject of separate schedulings.
All fences, road surfaces, signs, notices and services are excluded from
the scheduling, although the ground beneath these features is included.
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.
