Section of Cleave Dyke prehistoric boundary on Hambleton Down and World War II bombing decoy shelters north east and north of Garbutt Farm


Heritage Category: Scheduled Monument

List Entry Number: 1020105

Date first listed: 22-Dec-1994

Date of most recent amendment: 20-Jul-2001


Ordnance survey map of Section of Cleave Dyke prehistoric boundary on Hambleton Down and World War II bombing decoy shelters north east and north of Garbutt Farm
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The building or site itself may lie within the boundary of more than one authority.

County: North Yorkshire

District: Hambleton (District Authority)

Parish: Boltby

County: North Yorkshire

District: Hambleton (District Authority)

Parish: Sutton-under-Whitestonecliffe

County: North Yorkshire

District: Ryedale (District Authority)

Parish: Cold Kirby


National Grid Reference: SE 51296 84488


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

Reasons for Designation

The Cleave Dyke system is the most westerly of a series of dyke systems on the Tabular Hills of north east Yorkshire. The name has been given to a series of linear ditches and banks stretching north-south over 9km parallel with and close to the western scarp of the Hambleton Hills. The system was constructed between the Late Bronze Age and the Iron Age to augment the natural division of the terrain by river valleys and watersheds. Significant stretches remain visible as upstanding earthworks; elsewhere it can be recognised as a cropmark on aerial photographs. The system formed a prehistoric territorial boundary in an area largely given over to pastoralism; the impressive scale of the earthworks displays the corporate prestige of their builders. In some instances the boundaries have remained in use to the present day. Linear boundaries are of considerable importance for the analysis of settlement and land use in the later prehistoric period; all well preserved examples will normally merit statutory protection.

This part of the Cleave Dyke system lies in the mid-part of the Hambleton Hills and is preserved as standing earthworks, buried remains and pit alignments visible on aerial photographs. Significant information about the form, function and date will be preserved. The dyke is also associated with Bronze Age round barrows. These are funerary monuments with a ritual and social function which also acted as territorial markers in the area. Such groupings of monuments offer important scope for the study of the development and exploitation of the landscape during the prehistoric period. World War II saw the emergence of aerial bombardment as a decisive instrument of warfare, and to counter this threat, the United Kingdom maintained a flexible and diverse mechanism of air defence throughout the war. This included the early warning of approaching aircraft, through radar and visual detection, and the local defence of towns, cities and other vulnerable points using anti-aircraft gunnery and balloon barrages. But less conspicuously, many potential targets were shadowed by decoys - dummy structures, lighting displays and fires - designed to draw enemy bombs from the intended points of attack. Britain's decoy programme began in January 1940 and developed into a complex deception strategy, using four main methods: day and night dummy aerodromes (`K' and `Q' sites); diversionary fires (`QF' sites and `Starfish'); simulated urban lighting (`QL' sites); and dummy factories and buildings. In all, some 839 decoys are recorded for England in official records, built on 602 sites (some sites containing decoys of more than one type). This makes up the greater proportion of the approximately 1000 decoys recorded for the United Kingdom. The programme represented a large investment of time and resources. Apart from construction costs, several thousand men were employed in operating decoys, the fortunes of which were closely tied to the wartime targets they served. The decoys were often successful, drawing many attacks otherwise destined for towns, cities and aerodromes. They saved many lives. `K' sites (also known as Dummy Landing Grounds [Day] or DLG[D]) were intended to replicate RAF satellite airfields, rudimentary landing grounds used as an adjunct to permanent stations for the dispersed operation of aircraft. As such, the decoy consisted of simulated grass runways, simple technical and defensive structures including trenches, dummy aircraft, a windsock, petrol and bomb dumps represented by conspicuous dug-up areas, and a limited range of facilities for the crew manning the decoy. There were ten dummy aircraft allocated to each site, the type reflecting the function of the `parent' station. Forty-two decoys in England are recorded as having a `K' component, located mostly in eastern counties. The `Q' sites were intended to simulate the flarepath lighting of permanent RAF stations as a lure to attack by night bombers and intruder aircraft. The programme lasted until August 1944 during which time the lighting configurations changed periodically to shadow developments on real airfields. Common features of `Q' sites included the lighting arrangements and a night shelter. The night shelter is generally all that survives. In all, 236 sites with a `Q' component are recorded in England. These are distributed mostly in the east, and in central and southern England. Very little now survives of any of these decoys, most having been cleared after the war. All sites with significant surviving remains will be considered of national importance, as will those where a well-preserved night shelter has been identified. The shelters north and north west of Garbutt Farm survive well and significant information about their function within the decoy airfield and their role in the wider decoy network in the North East will be preserved.


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


The monument includes a section of the prehistoric linear boundary system on the Hambleton Hills, known as the Cleave Dyke system, and remains of a World War II dummy airfield located on level ground on the western edge of the Hambleton Hills. The Cleave Dyke includes standing earthworks, buried remains and pit alignments. Orientated north-south, parallel to the scarp slope, the dyke extends for 2.3km north from the north east corner of Cliff Plantation at NGR SE51618325, terminating 360m south east of Boltby Scar promontory fort at NGR SE50988541. Midway along its length there is a spur extending westwards for 230m, terminating at the scarp edge. The dyke comprises a ditch with a flanking bank, which together are up to 11m wide. To the north of Garbutt Farm are two sections of upstanding earthworks extending for 150m and 200m respectively separated by 150m where slight hollows representing the ditch can be identified. Each section of earthwork comprises a single ditch with flanking banks. The western bank is 4m wide and stands 1.1m above the base of the ditch and 0.3m high. The ditch itself is 4m wide and 0.9m deep. Elsewhere, where the earthwork has been levelled, the in-filled ditch can be traced on aerial photographs. Although levelled, significant archaeological remains are known to survive beneath the ground. There are two in-filled pit alignments, visible on aerial photographs, one marking the northern end of the dyke and the other 500m west of Dialstone Farm. It is thought that pit alignments may originally have been constructed to mark out the line of the wider dyke system, the line thus created being eventually replaced by the linear bank and ditch. Such a pattern of construction may explain the irregular line of the earthworks in this section. The northern end of the dyke represents an original gap in the Cleave Dyke system, which continues again 700m to the north, where it is the subject of a separate scheduling. At the southern end, the earthwork extends into the corner of a coniferous plantation between a field wall and a modern road, for a distance of 80m. The dyke has been levelled 40m from the southern end of this section and is no longer visible as an upstanding earthwork, although it will survive as a buried feature. To the north of this disturbance the dyke comprises a pair of low banks 50m in length with a partly filled in central ditch. The western bank is 4m wide and the eastern bank is 5m wide and it is filled in to the level of the surrounding ground. South of the levelled sections the eastern bank is visible as a linear bank, 7m long and 0.8m high. The ditch and western bank have been disturbed and are no longer visible as earthworks but are considered to be preserved as buried features. To the south the dyke is truncated by a modern road and car park but continues again 50m to the south east where it is the subject of a separate scheduling. The World War II dummy airfield site is located to the north and north east of Garbutt Farm. The site was intended to divert enemy aircraft from the satellite airfields attached to the parent bomber bases at RAF Dishforth and RAF Toplcliffe, located approximately 15km and 20km to the south west. It operated two versions of the decoy principle. One, code named `K', attempted to replicate the genuine airfields. A contemporary aerial photograph shows seven dummy Whitley bombers distributed across a wide area to the north and east of Garbutt Farm. The photograph also shows aircraft taxi marks, a dummy bomb dump surrounded by a protective blast wall with no attempt at camouflage and a genuine Tiger Moth bi-plane. The other type of decoy principle employed, code named `Q', simulated lighting for a night time operating airfield. The site was organised and operated by the parent stations, which also provided some of the personnel. The first reference to the `K' site was on 13th March 1940 and to the `Q' site on 19th June 1940. The `K' site ceased operations on 31st October 1941 but the site carried on the `Q' element until 12th August 1942. It is known that the site was subject to enemy air activity and bombing attacks. Whilst the primary purpose of the site was as an airfield decoy, the site also served as an diversionary landing strip for friendly aircraft in the event of fog in the Vale of York. The surviving remains of the decoy site are two shelters one of which was the night shelter, which controlled the `Q' site. The night shelter is located at NGR SE51538346 and lies approximately 10m to the west of the Cleave Dyke. It provided accommodation and protection for the operating crew, housed the generators powering the lights and provided communication, through a telephone line, to the parent station. The shelter follows a standard design issued by the Air Ministry (3395/40) in the spring of 1940. It is a brick and concrete built, partly sunken structure protected by earth banking and measures approximately 14m by 8m. Internally the shelter is composed of a set of steps leading to a central passage with the operating room to one side and the engine room to the other. The entrance way is protected by an external, brick blast wall. Although the internal fittings have been removed some structural elements such as ventilation vents in the engine room and the escape/observation hatch in the operating room can be identified. The other shelter is located at NGR SE51458356 and is partly built into the earthworks of the Cleave Dyke. It follows the same design as the night shelter only there is no engine room present. This building is probably a modified night shelter design, used for further accommodation and to act as an air raid shelter for the `K' site crew. The bomb dump visible on the aerial photograph no longer survives and is not included in the monument. The surface of the road to Garbutt Farm, the field walls and fences 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 4 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: 25564

Legacy System: RSM


Books and journals
CDA, , The Cleave Dyke System, (1976)
Dobinson, C S, Fields of Deception: Britains Bombing Decoys of WWII, (2000)
Harwood, J, Personal data base, (2000)
Spratt, D A , 'The Archaeological Journal' in The Cleave Dyke System, , Vol. YAJ 54, (1982), 33-55
Spratt, D A , 'The Archaeological Journal' in The Cleave Dyke System, , Vol. YAJ 54, (1982)
Spratt, D A , 'The Archaeological Journal' in The Cleave Dyke System, , Vol. YAJ 54, (1982), 33-52
Spratt, D A , 'The Archaeological Journal' in The Cleave Dyke System, , Vol. YAJ 54, (1982), 33-52
ANY 065/07, (1979)
ANY 169/07,
Held at NYCC, ANY065/07; ANY 63/18, (1979)
Thomas, R, (2000)

End of official listing