UKHillwalking
Article
UKHillwalking recently
published an article on the research and survey of Twyn Llech and its summit
position in relation to that of the border between Wales and England. The original article and a link to it on the UKHillwalking website appear below.
Will England Reclaim its
Share of a Welsh Mountain?
It's the high point near where the Welsh-English
border runs over the Black Mountains, but there all certainty ended. Should it
properly be called Black Mountain or Twyn Llech? And which country could
rightfully lay claim to the summit? Following research by two independent
surveyors, Myrddyn Phillips assisted by Mark Trengove, the mystery surrounding
one of the most visited hills in South Wales has finally been cleared up... with
a surprising conclusion.
Mark and I are
both keen hill walkers with a common interest in hill bagging and the
classification of hills. This particular hill was of interest, as its summit
position and the location of the border between England and Wales, in relation
to the summit, has been under debate. Was the summit on the Welsh side of the
border and therefore could the hill be claimed as being Welsh, or was it in
fact English? Our aim was to determine where the summit of the hill is
positioned, measure its height and plot the course of the border between Wales
and England as it crosses the summit plateau.
 |
| Twyn Llech |
The Name
Rising above the Vale of Ewyas on
its Welsh side, and the upper Olchon Valley on its English side, the hill is
known by many as Black Mountain; however
research suggests that it was supplanted by early hill-list compilers from the
old ridge name given to the main easterly spur of this hill range, and does not
apply to the hill itself. This easterly ridge is now known as the 'Hatterrall
Ridge' after its southerly outlier, Hatterrall Hill.
Enquiries with the local farming
community unearthed the feature name of 'The thieves' stone'. This name was
given by David Gains who farms in the Olchon Valley. David explained: 'It's
hanging out on a slope, straight on top of the ridge, just on the Welsh side
and about 3-4ft wide'. He first heard of this name from his
father, who passed on a saying: 'If a sheep grazed the land around the stone
and kept by the thieves' stone it would never get maggots'.
This name still appears on
contemporary Ordnance Survey maps in its Welsh form of Llech y Lladron, and is
given to a rock outcrop on the upper northerly section of the hill.
This and the name of Twyn Llech
are the two main named features on this hill, and it is the latter that many
know as this hill's referred to Welsh name, which can be translated as 'hill of
the stone (or crag)'. This name still appears on Ordnance Survey maps
positioned to the west of its summit. Therefore for the remainder of this
article we'll refer to the hill as Twyn Llech.
 |
| Llech y Lladron |
The Hill
Twyn Llech is positioned in the
Black Mountains in the south-eastern part of Wales. This hill range has four
main extended ridges oriented in a north-west to south-east direction, and Twyn
Llech is the highest point of the most easterly of these main ridges.
The hill comprises grass and
heather with a base of peat; it is not dramatic in nature but is a great bulk
of a hill. The high point is situated toward the northerly section of the main
easterly ridge, which extends for approximately 15km. It has two main
recognised and individual summits on it, one of which is Twyn Llech and the
second the southerly outlier Hatterrall Hill.
There are two significant marker
lines on contemporary Ordnance Survey maps that follow the course of this
easterly ridge. One is a public right of way that designates part of the Offa's
Dyke long distance footpath, and the other is the land border between Wales and
England. These are positioned next to one another on the maps. As the summit of
the hill is positioned to the west of the ridge path, it has generally been
accepted that it is therefore in Wales.
 |
| Part of the main eastern ridge |
Research
Prior to visiting the hill I conducted extensive research into the
position of the border between Wales and England. My hope was to find a written
document that gives detail of the position of this land boundary, and
especially for the course that it takes over the main easterly ridge of the
Black Mountains.
A number of individuals, public bodies and organisations were
contacted including the Powys Archives, Powys County Council, National Library
of Wales, Longtown Historical Society, Ewyas Study Group, Hereford Record
Office, Brecon History Society, Clwyd Powys Archaeological Trust, Hereford
Border Authorities, Electoral Services, Boundary Commission, Ordnance Survey,
HMSO, Electoral Commission, local historians and the Senedd. None of them could
either supply or give information on any form of written document relating to
where the land border between Wales and England is positioned. In fact many
said that such a document did not exist. The only organisation that gave any
indication as to where this border is positioned was the Ordnance Survey, and
they simply instructed me to consult their maps.
The Summit
The summit area of this hill comprises a broad ridge of grass and
heather with a base of peat. It is relatively flat. However, Twyn Llech has a
distinguishable rise on the northerly part of this land, and a dip that leads
south to another slight rise approximately 350 metres away, with the northerly
high point being relatively easy to distinguish and the southerly high point
comprising land that slightly undulates.
These two rises roughly match map detail. The Ordnance Survey give
a 703m spot height on their contemporary 1:50,000 Landranger and 1:25,000
Explorer maps, positioned in the southerly part of a 700m continuous contour ring
at SO 25586 35010. Harvey maps give a 706m spot height on their 1:40,000 Offa's
Dyke South map which is positioned in the northerly part of a 705m continuous
contour ring.
First on-site visit
This concentrated on determining the height and position of the
northerly high point and its counterpart to the south. This was conducted
during an extended walk I completed, taking in a number of other hills. This
also prioritised another hill to the south that was surveyed as having less
that 15m of drop and which is currently still listed as a Nuttall. The
conditions for each survey were excellent with good visibility and little
breeze.
The results of these two surveys are:
Northerly high point: 703.639m (converted to OSGM15) at SO 25520
35383
Southerly high point: 702.721m (converted to OSGM15) at SO 25572
35032
A Trimble GeoXH 6000 GNSS receiver was used to determine the
height of Twyn Llech and with a 0.9m difference in height there was confidence
that the northerly point is where the summit of Twyn Llech is positioned. As
the southerly land undulates a second survey to give correlation and
confirmation was sought, and the opportunity to do so came nine months later.
The Border
The second on-site visit gave Mark and I the opportunity to plot
the course of the land border on the ground as it passes over the summit
plateau of Twyn Llech. To do this we used a Garmin GPS Map 64s hand-held device
that has access to the Ordnance Survey 1:50,000 mapping. By following the
course of the border we determined that it was consistently positioned to the
east of the flagged ridge path, and the path itself is also positioned to the
east of the summit of both the northerly and southerly points. Having
determined where the border lay according to 1:50,000 map detail, we paced from
its position to where the Trimble was set up on the northerly summit and its
southerly counterpart, with the former being 50 metres and the latter being 45
metres in distance. Therefore, according to contemporary Ordnance Survey
1:50,000 mapping, the summit of Twyn Llech is in Wales.
However sometimes things aren't as simple as they appear...
The second on-site visit had two aims. Firstly we wanted to
determine the position of the land border according to Ordnance Survey 1:50,000
mapping, and secondly to take further data sets with the Trimble GeoXH 6000
from the northerly and southerly positions. The conditions for each survey were
again ideal with good visibility and not a breath of breeze. The Trimble was
placed on a rucksack, which was used as an improvised tripod to give elevation
above its immediate surrounds. Respective measurement offsets were taken
between its internal antenna and the ground below.
The results of these three further surveys appear below:
Northerly high point: 703.656m (converted to OSGM15) at SO 25520
35383
Southerly high point: 702.787m (converted to OSGM15) at SO 25558
35018
Southerly high point: 702.699m (converted to OSGM15) at SO 25566
35054
These results show excellent correlation with the first set of
survey data and confirm that the northerly point is where the summit of Twyn
Llech is positioned.
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| OS Six-Inch map published in 1887 that gives the border as the 'Watershed' |
The Ordnance Survey Base Map
Our on-site visit had confirmed where the summit of Twyn Llech is
positioned and had given the hill an accurate height. We now compared our
findings to the series of Ordnance Survey Six-Inch maps.
For many years the Ordnance Survey Six-Inch map was considered
their base map. This was the map for information to be fed onto. The scale was
superseded in the 1950s by the 1:10,000 series of maps and was available as
sheets until the 1980s when these maps were digitised. The Six-Inch map is
still one of the best for giving detail, either numeric or positional, and it
was this map that I turned to.
I consulted the series of Six-Inch maps and looked at detail
surveyed in 1887 and published in the same year. The land border between Wales
and England appears on this map as a split black line, as it does on the
publicly available scales of the 1:50,000 and 1:25,000 maps. However, the line
of this border on the Six-inch base map has one extremely important word
against it - 'Watershed'. The word 'Watershed' also appears beside this border
on the Ordnance Survey Vector Map Local that is hosted on the Geograph website
and entitled the Interactive Coverage Map. Therefore this word and its
implication have remained in the system of Ordnance Survey mapping for over 130
years.
Ordnance Survey Consultation
As there was discrepancy between our on-site findings using the
1:50,000 mapping and the Six-Inch and Vector Map Local maps the Ordnance Survey
were consulted and they kindly forwarded the following information:
"Ordnance Survey is not directed by the Ordnance Survey Act
1841 or any other Act to show National boundaries, although they are shown on
certain scales of mapping (1:50k / Landranger, does depict National Boundaries
between England-Wales, England-Scotland). In OS's most detailed mapping product
OS MasterMap the Welsh / English border is located accurately and correctly it
is displayed as a County/UA Boundary.
"OS's 1:25k and 1:50k leisure maps are purely contextual to
provide a navigational guide to the landscape. Given their scale, these maps
should never be used for measuring and surveying purposes. Our leisure maps are
derived from the accurate large-scale data but are generalised for clarity,
therefore not every feature is shown in the same position as the source data,
and we are satisfied with how they currently depict the location of the Welsh
English border."
MasterMap is the Ordnance Survey digitised mapping which receives
upwards of 10,000 individual updates per day, and as its name implies, this is
the master map for Ordnance Survey data.
I was advised by Ordnance Survey that the placement of the border
on MasterMap is 12 metres to the east of the grid coordinates I supplied them
for the summit of Twyn Llech, meaning that MasterMap places the summit of this
hill in Wales.
Boundary Commission for Wales Consultation
After consultation with Ordnance Survey I was advised to contact
the Boundary Commission for Wales. If a change in border placement is required
it is this organisation that would initiate it. They told me:
"There is no legal mechanism for reviewing the boundary
between England and Wales. The boundary is fixed and would require primary
legislation to develop a mechanism to make a change to it. The England-Scotland
boundary does have such a mechanism and the review is performed jointly by the
English and Scottish Boundary Commissions.
"As far as the Commission is concerned the boundary provided
by Ordnance Survey, particularly that in its MasterMap product, is the
definitive boundary.
"With regard to the specific area to which you referred, I
confirm that it is the convention of this Commission that if we were to draw a
boundary that it would follow either the top of a ridge-line to its peak or the
bottom of a valley depending on the circumstance; where we are not following
another easily identifiable boundary (road, railway line, centre of a river,
etc.). It may be that when the boundary was originally drawn at the larger
scale that that was the intention. We have no records which would ascertain
that intention."
Conclusion
My conclusion from the research and survey I've conducted is that
the border should be moved and placed on MasterMap going through the summit of
Twyn Llech and that primary legislation should be initiated to instigate the
mechanism required for such a change. This is based on the convention the
Boundary Commission for Wales would adopt and the evidence that the border
followed the watershed on this hill's summit plateau on selective Ordnance
Survey maps for over 130 years. It is also based on the simple fact that it is
the natural course of any boundary on an open mountain such as Twyn Llech to
follow the ridge crest which is also the watershed. The simple fact of the
matter is that no one had ever surveyed this hill for where its summit is
positioned prior to our visit, therefore the border placement on MasterMap
although very close to the summit is still 12 metres from it and in all
probability was placed to the best of the respective cartographer's presumption
of where the watershed is positioned.
So which nation rightly lays claim to the summit of Twyn Llech?
I'd say both. If the reinstated course of the border is accepted then it can be
considered a dual national hill.
Myrddyn Phillips with Mark Trengove
