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

A Scheduled Monument in Boltby, North Yorkshire

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Latitude: 54.2519 / 54°15'6"N

Longitude: -1.2138 / 1°12'49"W

OS Eastings: 451321.285078

OS Northings: 484311.231393

OS Grid: SE513843

Mapcode National: GBR MMZ8.0K

Mapcode Global: WHD8K.BD78

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

Scheduled Date: 22 December 1994

Last Amended: 20 July 2001

Source: Historic England

Source ID: 1020105

English Heritage Legacy ID: 25564

County: North Yorkshire

Civil Parish: Boltby

Traditional County: Yorkshire

Lieutenancy Area (Ceremonial County): North Yorkshire


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

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.

Source: Historic England

Reasons for Scheduling

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
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
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.

Source: Historic England


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)

Source: Historic England

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