Friday, 31 July 2020

Mapping Mountains – Hill Reclassifications – The Fours


Lord’s Seat (NT 912 079) – 390m Sub-Four reclassified to 390m Double Sub-Four

There has been a reclassification to the listing of the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill confirmed by LIDAR analysis.


This spreadsheet is being evaluated by DoBIH Editors and others, and for this particular hill it was Jim Bloomer who initially assessed its height and that of its adjacent peak via LIDAR analysis.

Myrddyn Phillips then evaluated this hill’s details via LIDAR analysis and confirmed its drop value and hence its reclassification.

LIDAR image of Lord's Seat (NT 912 079)

The criteria for the list that this reclassification applies to are:

The FoursThe 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main listing of The Fours are three categories of sub hills, with this hill being reclassified from the 390m Sub-Four category to the 390m Double Sub-Four category.  The criteria for 390m Sub-Four status being all English hills at or above 390m and below 400m in height that have 30m minimum drop and the criteria for 390m Double Sub-Four status being all English hills at or above 390m and below 400m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24th April 2018.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Lord’s Seat, and it is adjoined to The Cheviot group of hills, which are situated in the north-eastern part of England (Region 33 Scottish Border to the River Tyne), and it is positioned with a minor road to its south-east and farther afield has the A68 road to its south-west, the B6341 road to its south-east and the A697 road to its east, and has the town of Rothbury towards the east south-east.

When the 2nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, this hill was listed as a 390m Sub-Four with an estimated c 53m of drop, based on the 392m summit spot height and an estimated c 339m col height based on interpolation of 10m contouring between 330m – 340m that appear on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

Extract from the Ordnance Survey 1:25,000 Explorer map

Approximately 1km to the south-west of the summit of Lord’s Seat is the triangulation pillar on the hill named Green Side.  The flush bracket adjoined to this trig pillar is given as 389.534m and positioned at NT 90299 07313 in the OS Trig Database, with its map height given as 389m.  As the map height of Green Side is lower than Lord’s Seat the former was unclassified with an estimated c 17m of drop and Lord’s Seat listed as the 390m Sub-Four.

However, it was not until LIDAR became available that the details for these two hills could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.


LIDAR results for each summit:

Lord’s Seat:  392.2m at NT 91281 07968 and NT 91282 07966

Green Side:  395.5m at NT 90695 07602


As Green Side is higher than Lord’s Seat the respective cols are swapped and Green Side becomes the 390m Sub-Four.  However, the subsequent drop for Lord’s Seat is sufficient for it to be classified as a 390m Double Sub-Four.

LIDAR image of Lord's Seat and Green Side

Therefore, the reclassification of Lord’s Seat from 390m Sub-Four status is due to LIDAR analysis, resulting in a 392.2m summit height and a 370.9m col height, with these values giving this hill 21.3m of drop, which is insufficient for 390m Double Sub-Four status.


The full details for the hill are:

Group:  The Cheviot

Name:  Lord’s Seat

OS 1:50,000 map:  80

Summit Height:  392.2m (LIDAR)

Summit Grid Reference:  NT 91281 07968 and NT 91282 07966 (LIDAR)

Col Height:  370.9m (LIDAR)

Col Grid Reference:  NT 90985 07852 (LIDAR)

Drop:  21.3m (LIDAR)


For the additions, deletions and reclassifications to The Fours reported on Mapping Mountains since the December 2013 publication of the list by Europeaklist please consult the following Change Registers:











Our thanks to Joe Nuttall and Jim Bloomer for bringing the details of this hill to our attention.

Myrddyn Phillips and Aled Williams (July 2020)





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