Slight univallate hillfort on Wilbury Hill


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
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The building or site itself may lie within the boundary of more than one authority.

North Hertfordshire (District Authority)
North Hertfordshire (District Authority)
North Hertfordshire (District Authority)
Letchworth Garden City
National Grid Reference:
TL 20228 32451

Reasons for Designation

Slight univallate hillforts are defined as enclosures of various shapes, generally between 1ha and 10ha in size, situated on or close to hilltops and defined by a single line of earthworks, the scale of which is relatively small. They date to between the Late Bronze Age and Early Iron Age (eighth - fifth centuries BC), the majority being used for 150 to 200 years prior to their abandonment or reconstruction. Slight univallate hillforts have generally been interpreted as stock enclosures, redistribution centres, places of refuge and permanent settlements. The earthworks generally include a rampart, narrow level berm, external ditch and counterscarp bank, while access to the interior is usually provided by two entrances comprising either simple gaps in the earthwork or an inturned rampart. Postholes revealed by excavation indicate the occasional presence of portal gateways while more elaborate features like overlapping ramparts and outworks are limited to only a few examples. Internal features included timber or stone round houses; large storage pits and hearths; scattered postholes, stakeholes and gullies; and square or rectangular buildings supported by four to six posts, often represented by postholes, and interpreted as raised granaries. Slight univallate hillforts are rare with around 150 examples recorded nationally. Although on a national scale the number is low, in Devon they comprise one of the major classes of hillfort. In other areas where the distribution is relatively dense, for example, Wessex, Sussex, the Cotswolds and the Chilterns, hillforts belonging to a number of different classes occur within the same region. Examples are also recorded in eastern England, the Welsh Marches, central and southern England. In view of the rarity of slight univallate hillforts and their importance in understanding the transition between Bronze Age and Iron Age communities, all examples which survive comparatively well and have potential for the recovery of further archaeological remains are believed to be of national importance.

Despite changes in agricultural use and other developments, the greater part of the slight univallate hillfort on Wilbury Hill remains relatively undisturbed, and is known from limited excavation to retain highly significant archaeological information. The circuits of defences have been clearly identified from aerial photography, and the buried remains of both the banks and ditches are known to contain valuable evidence concerning the methods used in the construction of the hillfort and its changing appearance throughout its use. Limited excavations have demonstrated that the complex arrangement of buried internal features shown in the aerial record is well preserved and contains detailed information relating to the function of the hillfort and the lifestyle of its occupants. Wilbury Hill forms part of a series of defended sites which developed along the Chiltern ridge in the Late Bronze Age and Iron Age, of which the promontory fort at Sharpenhoe Clappers (approximately 14km to the WSW) and the slight univallate hillfort of Arbury Banks (approximately 9km to the north west) are the nearest examples. Comparisons between these sites will provide important information concerning the development of this monument form through time, and the nature of the prehistoric societies involved in their construction.


The monument includes the visible and buried remains of a slight univallate hillfort occupying the crest and part of the south facing slope of Wilbury Hill, a broad promontory on the western outskirts of Letchworth with extensive views over Hitchin to the south and across the chalk escarpment to the south west. The hillfort is defined by two adjoining circuits of defences formed by single banks and external ditches. These are no longer conspicuous on the ground, although distinct cropmarks generated by the buried features have been recorded by aerial photography since the 1950s. The enclosures are best defined to the south of Icknield Way, a modern road which broadly follows the route of a prehistoric trackway of the same name. The smaller, eastern enclosure is sub-circular in plan and measures approximately 200m in diameter, lying partly in a field and partly beneath allotment gardens established in the mid-1970s. The larger circuit extends westwards to form a broad semicircular outer enclosure, the western side of which is marked by the present line of Stotfold Road. The circuits are believed to have converged to the north of Icknield Way, although this area is obscured by a large municipal cemetery which is not included in the scheduling. Earthworks representing the combined southern arc of the two enclosures remained clearly visible until the middle of the 19th century when, for agricultural reasons, the ditches were filled with material from the banks to leave only a slight visible scarp. The only substantial section of the bank to remain forms part of the verge along the eastern side of Stotfold Road. The external ditch at this point is buried beneath the modern carriageway, and is included in the scheduling. In 1933 limited excavations across the southern perimeter uncovered the bases of the banks, which measured up to 8m in width and contained evidence of timber frameworks and revetment. The defences were found to have been constructed in two phases. The first, a narrow palisade with traces of an incomplete bank, is now thought to date from the Late Bronze Age (c.700 BC). In the Middle Iron Age (c.400 BC), more substantial banks were constructed on the earlier alignments and accompanied by large external ditches. The excavation of the latter, which were found to measure some 8m across and 2.7m in depth, may have removed evidence of shallower versions flanking the earlier palisades. Evidence of burning and collapse suggests that the later banks were relatively short lived, although occupation is thought to have continued on a limited scale within the denuded ramparts. The 1933 excavations demonstrated that access to the eastern enclosure was controlled by a sequence of timber gateways, the final version of which was linked to an unexcavated causeway across the southern arc of the ditch. A further causeway has been identified within the line of cropmarks which mark the western arc of the eastern circuit, and therefore presumably linked the two enclosures. Small excavations to the north of the southern entrance in 1929 and 1933 found the remains of hearths, flint-cobbled surfaces, refuse or storage pits and evidence for huts. These features are now thought to span the period from the Late Bronze Age to the Late Iron Age, occupation giving way to agricultural use after the Roman Conquest. Aerial photography has since demonstrated an extremely dense pattern of circular and linear markings within the eastern enclosure which reflect numerous huts, pits and gullies. The western enclosure has revealed few such anomalies, although a minor excavation in the northern part of this area in 1959 found evidence for activity in the form of early Iron Age pottery, a broken spindle whorl and fragments of human remains. Human burials were also found in 1933, in the base of the western enclosure ditch, within the southern interior of the eastern enclosure and beneath a flint surfaced causeway which had been laid over the western ditch in the Late Iron Age. A large number of Roman coins were collected by the local antiquarian William Ransome when the extreme northern corner of the western enclosure was quarried for railway ballast in the mid-19th century. Ransome's collection, when combined with earlier reports of Roman artefacts from the site, clearly indicates some form of occupation continued within part of the former hillfort, perhaps focussed at the junction of the prehistoric trackway and a Roman route to Ninesprings villa, perpetuated by Stotfold Road. The quarry floor lies well below the level of archaeological remains and is excluded from the scheduling, although the quarry walls (which cut through evidence of occupation) are included. A cropmark ditch running across the field to the south of the hillfort at a distance of 100m from the southern ramparts is visible in the aerial record. This feature continued into the area of Fearnhill School, where it was partly excavated in 1972 and found to contain fragments of Iron Age pottery. This ditch is not included in the scheduling. A second ditch, also visible as a cropmark, extends southwards from the western enclosure across the line of the southern ditch. This is also believed to be contemporary with the occupation of the hillfort and is therefore included in the scheduling together with its junction with the southern ditch. A number of features are excluded from the scheduling: these are all fences and fence posts, the surfaces of all carriageways, paths and drives, all sheds and other temporary structures within the allotments, and all telephone poles and street lights; the ground beneath these items is, however, included. The floor of the quarry in the north west corner of the site is totally excluded from the scheduling.

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


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

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Books and journals
Camden, W, Britannia, (1695), 46
Cussans, J E, History of Hertfordshire, (1876), 5
Applebaum, E S, 'Arch J' in Excavations at Wilbury Hill, an Iron Age Hillfort nr Letchworth, (1951), 12-37
Applebaum, E S, 'Arch J' in Excavations at Wilbury Hill, an Iron Age Hillfort nr Letchworth, (1951), 12-37
Moss-Eccardt, J, 'Beds Arch J' in Excavations At Wilbury Hill 1959, , Vol. 33, (1964), 34-46
Pollard, J, Hamilton, M, 'Beds Arch J' in Recent Fieldwork at Maiden Bower, , Vol. 21, (1994), 10-18
info from County Archaeologist, Bryant, S, Wilbury Hill, (1996)
info from District Archaeologist, Burleigh, G, Wilbury Hill (allotments), (1996)
info from District Archaeologist, Burleigh, G, Wilbury Hill, (1996)
Matthews, K, Wilbury Hill, 1990, Compilation plan (AP and excavation)
Matthews, K, Wilbury Hill, 1990, Compilation plan (unpublished)
NMP data on Herts County Council GIS, RCHME, Wilbury Hill, (1996)
Oblique monochrome AP, Potato Marketing Board, AP 3524, (1975)
Oblique monochrome APs, CUCAP, ABV 35, ABW 50, BIZ 46, BQV 42 (1974), HH 73 (1952),
Oblique monochrome APs, CUCAP, ABV 35, ABW 50, BIZ 49, BQV 42 (1974), HH 73 (1952),
Oblique monochrome APs, Letchworth Museum, AP 12/13, (1976)
Rectified plot, RCHME data on CC GIS, Herts County Council, Wilbury Hill, (1996)
Schedule entry file map, Wilbury Hill Camp (SAM HT 42), (1975)
Schedule entry SM:27199/AI:142021, Went, D A, Maiden Bower, (1996)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

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