Bagging Series

the Welsh P30s - An Epic Hill List

With over 2300 entries in Wales alone, the P30s are one of the more challenging of hill lists. Though the Welsh P30s have yet to be completed, hill height expert Myrddyn Phillips has ticked off an impressive 1000. To mark this milestone, he explains here the definition and origins of the P30s, and also their attraction. 

No match for crag id:"Bryn y Fan" – completing 1000 Welsh P30s

I’d purposely avoided visiting Bryn y Fan for many years as I thought it would eventually make an ideal hill on which to complete my 1000th Welsh p30. It has a large car park, a well maintained path to its summit and is relatively close to where I live. It is also a prominent hill and is listed as a Marilyn and Pedwar; providing the weather gods were kind its summit would give extended views.

Fourteen of us met in the car park at the base of Bryn y Fan at 12.00 midday on Saturday 15th April, many being friends who I’ve shared past hill celebrations with, others friends who I’d never visited a P30 with before. Old and new felt fitting for such an occasion.

Myrddyn (left) with Alex Cameron on Bryn y Fan  © Myrddyn Phillips
Myrddyn (left) with Alex Cameron on Bryn y Fan
© Myrddyn Phillips

As we set off the last of the morning’s showers disappeared into a clearing sky, and although a chill wind blew it would remain dry for the duration of our walk; the weather gods were indeed being kind.

A green track led down from the car park under the earthen sides of the Bwlch-y-gle dam before heading up the slopes of Bryn y Fan.  As we gained height Llyn Clywedog glimmered below as with patches of whiteness now developing in the sky. Across the intervening valley the shapely profile of Bryn y Tail stood proud. The green track continued toward the upper part of the hill which consists of heath and moor, only diverting from the summit just below it, and therefore we continued on a sheep path to the high point.

This is a small rocky knoll a few metres from its trig pillar. As I walked toward it some of my companions formed an arch with their walking poles for the ceremonial last few metres to the summit. This was the first time I’d walked through a ceremonial arch of walking poles, and I quite enjoyed it!

Reaching the top was the fulfilment of many years of hill walking and it was good to share it with so many friends. As photographs and videos were taken I called Alex Cameron over as he had achieved his 1000th Welsh P30 about an hour before our ascent of Bryn y Fan. We stood beside the summit, posed for a few photographs and quickly dashed down on the leeward side out of the wind to de-camp for drinks and lots of cake.

It had been an excellent day and my thanks to everyone who attended. It was good to share my 1000th Welsh P30 with such good friends.

"My approach only chipped away on the periphery, with other things, such as life, occasionally getting in the way of major hill bagging activity..."

Autumnal light on Aran Fawddwy  © Myrddyn Phillips
Autumnal light on Aran Fawddwy
© Myrddyn Phillips

So what is a P30 anyway?

P30 is an abbreviated term for hills that have 30m minimum prominence, with the ‘P’ standing for ‘Prominence’ and the ‘30’ standing for 30m.

Simply put, prominence is the vertical height gain between col and summit, or to put it more fully the height difference between summit and col connecting the hill to the next higher summit along the watershed.

The term prominence is relatively new in Britain, with its use having been adopted from prominence based groups in America. Prominence is also referred to in Britain as ‘drop’ or 'reascent’, with the former being the drop in height from summit to col, and the latter being the height from col to summit.

Using prominence in a hill list’s criteria gives the list compiler a useful tool to differentiate between one hill’s inclusion on a list over and above another's, bringing objectivity to what could otherwise becoming a subjective judgement.

Use of prominence has shaped most hill lists, and although list compilers have experimented with many other forms of qualification, including remoteness and dominance, the popularity of using prominence speaks for itself. In short, it works and it produces listings that are understood and popular for the hill bagger.

Allt Dolanog on a quiet frosty morning  © Myrddyn Phillips
Allt Dolanog on a quiet frosty morning
© Myrddyn Phillips

The origins of P30s

The use of prominence (albeit by any other name) was established when early hill list compilers such as John Rooke Corbett (1) and Edward Moss (2) used single ring map contours to differentiate between one hill’s inclusion and another. This was then developed in 1925 by Carr and Lister (3) using 100ft minimum prominence describing it as; ‘if it rose by more than 100 feet above the lower ground connecting it with any greater height’. By using P100ft Carr and Lister paved the way for this imperial height to be subsequently used by its nearest whole numbered metric equivalent of 30m.

In 1984 the use of P30m was first employed by Terry Marsh (4); and subsequently used by many other list authors including Michael Dewey (5), Alan Dawson (6), Myrddyn Phillips (7), Clem Clements (8) and Mark Jackson (9). By doing so each in turn is following an imperial height value that has been metricised. Although imperial measurement is only used by a few nations worldwide there is an erroneous quaintness about this that seems to predominate many British listings as we rely upon it even when listing hills using metric measurement!

Approaching the Carneddau from Cwm Pen Llafar  © Myrddyn Phillips
Approaching the Carneddau from Cwm Pen Llafar
© Myrddyn Phillips

Pushing the boundaries

Listing hills can become an addiction; there is eloquence to the procedure and fulfilment of purpose as each height band and contour checked produces another qualifying hill on the list. This procedure is time consuming, yet it can be therapeutic in its complicated simplicity. The procedure of using P30 has produced popular listings and pushed the boundaries of map study, which took many years of laborious work and which was conducted by a few dedicated people. 

A brief synopsis of published lists using P30m follows:

Terry Marsh – Welsh P30s at and above 600m in height

Michael Dewey – English, Manx and Welsh P30s at and above 500m and below 2000ft (609.6m) in height

Alan Dawson – Scottish, English and Welsh P30s at and above 600m in height (accumulated from various personal listings).

Myrddyn Phillips – English, Manx and Welsh P30s at and above 400m and below 500m in height.  Welsh P30s at and above 30m and below 400m in height.

Clem Clements – Scottish, English and Welsh P30s at and above 300m in height and below 600m in height.

These listings by Michael Dewey, Alan Dawson, Myrddyn Phillips (that's me!) and Clem Clements formed the bulk of the Tumps (thirty metre prominences and upward) that Mark Jackson duplicated when he collated the listing of Tumps in 2009. This list finally combined the other P30 lists under one title, and resulted in 16,800 British hills with their number increasing on a near weekly basis as new hills are added.  

Sunset beside Ynys Enlli from the end of the Llŷn peninsula   © Myrddyn Phillips
Sunset beside Ynys Enlli from the end of the Llŷn peninsula
© Myrddyn Phillips

Personal achievement

I started bagging Welsh P30s 17 years ago, concentrating on the Deweys, and later the Pedwar hills (see UKH article here). However, these and their higher counterparts of Welsh Hewitts are mere sub lists within the whole. 

When the remaining Welsh P30 lists were published in 2004 I knew a mainland completion was feasible. With over 2300 P30s, Wales lends itself to this. Some are on islands which pose their own access difficulties, but setting these aside leaves a mainland completion that will one day, no doubt, be achieved. I did wonder if I could attain this but my approach only chipped away on the periphery with other things, such as life, occasionally getting in the way of major hill bagging activity. Nevertheless my total crept upward and toward the end of 2015 I checked my bagging journals against all my updated lists and my total was just over 960. A number of unplanned events meant that a September 2016 finish for my 1000 Welsh P30 was postponed to April of this year.

Praising the P30s

Visiting smaller heighted Welsh hills whose prominence is at least 30m has opened great swathes of the country that I love, and otherwise would not have visited if not for this esoteric hobby.

It is difficult to pick favourites as memories of good days on the hill abound, many of which have been spent with friends; however it is memories that concentrate on small detail that come to the fore, such as the high Aran when illuminated with late autumnal light, and the early sun silhouetting my local hills of the Breiddin, or the slow sinking of the sun beside Ynys Enlli from the end of the Llŷn peninsula. Such experiences are vivid and leave a fleeting sense of awe.

My pursuit of Welsh P30s has been enhanced of late by visiting islands and also surveying many marginal candidates with the Trimble GeoXH 6000, which is a versatile piece of highly accurate equipment. Using the Trimble has promoted and also demoted a great number of hills from P30 status. Visiting islands and establishing an accurate summit height has proved fulfilling and also adventurous, and both were combined on Ynys Fach, which is a tidal island attached to the Pembrokeshire coast. A near vertical descent to the island’s connecting land bridge scouted by Rob Woodall who is the leading British P30 bagger, gave an adventurous ending to a day consisting of visiting a number of islands including The Smalls which are the furthest westerly land mass in Wales, with the evening’s activities resulting in Ynys Fach being deleted from P30 status.

An early winter's morning on the summit of Cnicht  © Myrddyn Phillips
An early winter's morning on the summit of Cnicht
© Myrddyn Phillips

The acceptance of man-made or artificial hills by many in the hill bagging community has led to a multitude of new entries to P30 listings, with some such as Bersham Bank (SJ311481) and Pandy Bank (SJ336538) being the result of stabilised waste spoil from old mining activity, whilst Y Ceiliog Mawr (the big cockerel) (SH594598) is an impressive lump of rock left in situ in the slate mines close to Llanberis and poses a major problem to Welsh P30 mainland completion.

However, above all is the memory of winter and those days that strike a chilled crispness when snow embeds the land and the hills take on a magical quality unlike any other, memories of an early morning on Cnicht when the world seemed at peace and the dash of a dog fox brought colour to an otherwise white land, or the approach to the high Carneddau from Cwm Pen Llafar and the quiet solitude of Carnedd y Filiast in the Arenig after hours of breaking trail through deep snow, all of these memories will last a lifetime.


1911 John Rooke Corbett ‘Twenty-Fives’ published by the Rucksack Club Journal (1)

1933 Edward (Ted) Moss ‘Some New Twenty-Fives’ published by the Rucksack Club Journal (2)

1940 Edward (Ted) Moss ‘The Two-Thousands of Wales’ published by the Rucksack Club Journal

1925 Herbert R C Carr and George A Lister ‘The Mountains of Snowdonia’ published by John Lane The Bodley Head Limited of London (3)

1984 Terry Marsh ‘The Summits of Snowdonia’ published by Robert Hale (4) 

1985 Terry Marsh ‘The Mountains of Wales’ Hodder and Stoughton

1995 Michael Dewey ‘Mountain tables’ published by Constable (5)

1995 Alan Dawson ‘The Murdos’ published by TACit Tables (6)

1997 Alan Dawson ‘The Hewitts and Marilyns of Wales’ published by TACit Tables

1997 Alan Dawson ‘The Hewitts and Marilyns of England’ published by TACit Tables

1999 Alan Dawson ‘Corbett Tops and Corbetteers’ published by TACit Tables

2004 Alan Dawson ‘Graham Tops and Grahamists’ published by TACit Tables

2002 Myrddyn Phillips ‘400m hills of England, Isle of Man and Wales’ published on the RHB Yahoo Group file database, with subsequent publications in 2004 ‘The Welsh 400 Metre Peaks’ on website and 5everdene website, following co-authored with Aled Willams 2013 ‘Y Pedwarau’ by Europeaklist, 2014 ‘Y Pedwarau’ by Haroldstreet and 2017 ‘Y Pedwarau’ by Mapping Mountains (7)

2004 Myrddyn Phillips ‘The Welsh 300 Metre Peaks’ (and 2006 published on the RHB Yahoo Group file database) , ‘The Welsh 200 Metre Peaks’, ‘The Welsh 100 Metre Peaks’ and ‘The Welsh 30m – 99m Peaks’ published by website and 5everdene website

Dates of publication unknown (to me) Clem Clements produced P30 listings to the 300m – 500m hills of Scotland, England and Wales with a variety of other prominence based listings also compiled (8)

2009 Mark Jackson ‘Tumps’ published on the RHB Yahoo Group file database (9)


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