Buckinghamshire Grim's Ditch: 660m long section to the west of Walter's Ash


Heritage Category: Scheduled Monument

List Entry Number: 1021193

Date first listed: 02-Nov-2003

Date of most recent amendment: 24-Feb-2004


Ordnance survey map of Buckinghamshire Grim's Ditch: 660m long section to the west of Walter's Ash
© Crown Copyright and database right 2018. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2018. All rights reserved. Licence number 102006.006.
Use of this data is subject to Terms and Conditions.

The above map is for quick reference purposes only and may not be to scale. For a copy of the full scale map, please see the attached PDF - 1021193 .pdf

The PDF will be generated from our live systems and may take a few minutes to download depending on how busy our servers are. We apologise for this delay.

This copy shows the entry on 14-Dec-2018 at 01:22:28.


The building or site itself may lie within the boundary of more than one authority.

County: Buckinghamshire

District: Wycombe (District Authority)

Parish: Bradenham

National Grid Reference: SU 83307 98125


Legacy Record - This information may be included in the List Entry Details.

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.


Legacy Record - This information may be included in the List Entry 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.


The contents of this record have been generated from a legacy data system.

Legacy System number: 35331

Legacy System: RSM


Books and journals
Network Archaeology, , Grim's Ditch: Archaeological and Management Survey Phase III, (1999)

End of official listing