Relative hills

In Chapter 1 of his book The Relative Hills of Britain, Alan Dawson suggests that:

The listing of some hills in Southern England gives hill walkers unfortunate enough to live in that part of the country some constructive walking to do when they're not away in the northern hills.

Dawson's book dispenses with the common assumption that a hill must be 2000 feet high to be worth climbing. Instead it concentrates on listing all the hills that are relatively high, compared to the surrounding land, rather than compared to sea level.

After giving his reasons for producing yet another list of British hills, Alan Dawson noted:

… the uncomfortable feeling that a lot of the minor summits which have appeared in previous lists are really a bit on the boring side. The more distinct hills usually provide enjoyable walks and good viewpoints, and it is very satisfying to plan and follow a long continuous route taking in as many tops as possible. But after walking an extra two or three miles just to stand on top of a flattish rounded hump that happens to be a few metres higher than the surrounding bog, then even the most obsessive of summit baggers begin to ask questions.

Fortunately, the hills to the south of London don't suffer from surrounding bog. But the problem of 'a lot of the minor summits which … are really a bit on the boring side' is particularly acute, as most of the summits to the south of London are located on long ridges of comparatively uniform height. To deal with this problem, Alan Dawson suggested using an objective measure of what makes a separate hill:

In the Andes or Himalaya most summits with a drop of only 500 feet would hardly warrant a second glance. In Britain 500 feet is significant, and seems a good measure of what makes a separate hill or mountain - it feels right. Well, almost right. Now that Ordnance Survey maps have metric contours, it is impossible to work in feet. Five hundred feet is equal to 152.4 metres, so to make matters easier the metric measure of 150 metres (492 feet actually) has been used to compile the new list.

Having settled on the type of hills to be included in the new list, it is of course vitally necessary to find a name for them. A flippant item in a recent Scottish Mountaineering Club Journal suggested using the term 'Mungo' for all the millions of hills over 300 feet high. I have decided to use the more distinguished and appropriate term 'Marilyn', and I therefore officially define a Marilyn as any hill that has a drop of at least 150 metres on all sides, regardless of distance, absolute height or topographical merit. At the last count there were 1542 of them, and they are all listed in Chapters 3 and 4 [of The Relative Hills of Britain].

[As the Wikipedia article on Marilyn (hill) (since modified) spelt out, the name Marilyn 'was coined as a humorous contrast to the designation Munro, used of a Scottish mountain with a height of more than 3,000 feet, which is homophonous with (Marilyn) Monroe'.]

Detling Hill

However, on completing the North Downs Way (for the second time), it occurred to me that the Marilyns were not quite adequate as a way of characterising the high points of southern England, as they did not define a representative top for each geologically and topographically significant mass of upland.

To take the North Downs as an example: ideally, there should be a representative top for each section between river valleys. The Marilyns provide only a partial answer:

Examining the OS maps, it appeared that the two ‘missing’ North Downs tops were the trig point at TQ112490 (to represent the Wey to the Mole) and the trig point at TQ593600 (to represent the Darent to the Medway).

Looking for an alternative system of identifying tops that would include these two points as tops, I came across the HuMPs - which are defined in exactly the same way as Marilyns, but are tops with a relative height of 100 m, rather than 150 m. HuMPs retain the distinct advantage that Marilyns have of avoiding subjective judgement, but seem to be better at characterising the topography of southern England.

The only list of HuMPs I could find was at The Mountains of England and Wales, Simon Edwardes' website for hill walkers and summit-baggers. He explained that:

The HuMPs are a list of hills with relative height over 100 metres, extracted from two other lists, the Yeamans (Scotland) and Clements (England, Wales and Isle of Man). (Note that these two lists include additional hills with less than 100m prominence). By definition, all Marilyns qualify as HuMPs (but not vice versa).

The collective name for these peaks was agreed upon by the RHB community as HuMPs which stands for HUndred Metre Prominences.

[The RHB community is a Yahoo Group. It is described as "Hillwalking in the UK, particularly climbing Marilyns. Intended for members of the Marilyn Hall of Fame and other Marilyn baggers. RHB stands for The Relative Hills of Britain, a book which lists all the British Marilyns (hills of any height with 150 metres drop all round)".]

In Simon Edwardes' list, a spot height of 227 m at TQ104490, shown on the OS 1:25000 map, is given as a top, rather than the trig point at TQ112490, and is called Dunley Hill (after Dunley Wood). The trig point at TQ593600 is identified as a top, and is called Wrotham Hill (after the nearby village).

Some of the names given to the tops in Simon Edwardes' list do not appear on the OS maps (because some of the tops are quite uninteresting to anyone other than a peak bagger, and so have not acquired a name), and in some instances I don’t think that the most appropriate name has been chosen - for example, Dunley Hill would probably be better called Hackhurst Downs. However, I have retained the names for the sake of consistency.

OS 1:25000 map

Image produced from the Ordnance Survey Get-a-map service. Image reproduced with kind permission of Ordnance Survey and Ordnance Survey of Northern Ireland.

It is of course possible to define increasingly inclusive sets of tops on the Marilyn principle by progressively reducing the relative height. Within the region The Relative Hills of Britain designates as Region 42, South-East England and the Isle of Wight, there are 15 Marilyns (relative height 150 m) and 36 HuMPs (relative height 100 m). It would be interesting to know the statistical relationship between the number of tops included and the relative height selected. I think it must be a power law, but I have not done the analysis.


A list of the relative hills south of London

36 HuMPs have been identified in the region The Relative Hills of Britain designates as Region 42, South-East England and the Isle of Wight. Of these, fifteen are also Marilyns (by definition, all Marilyns qualify as HuMPs). However, only 28 of the hills are in the region covered by this site. They are listed below. Of the remaining eight hills, six are on the Isle of Wight; one, Walbury Hill (a Marilyn), is a distant outlier in the North Wessex Downs; and one, Ashley Hill, is in Berkshire, just west of Maidenhead.

HuMPs south of London
Height (m) Name Grid Ref Marilyn ?
295 Leith Hill TQ139431 Yes
280 Black Down SU919296 Yes
272 Gibbet Hill SU900359 No
270 Butser Hill SU716203 Yes
267 Botley Hill TQ396553 Yes
261 Holmbury Hill TQ104429 No
255 Littleton Down SU941150 No
249 Wheatham Hill SU731277 No
248 Ditchling Beacon TQ331130 Yes
248 Linch Down SU848174 No
248 Toys Hill TQ469520 No
242 Crowborough TQ510305 Yes
238 Chanctonbury Hill TQ134120 Yes
235 Reigate Hill TQ255521 No
235 Wrotham Hill TQ593600 No
227 Dunley Hill TQ104490 No
217 Firle Beacon TQ485059 Yes
217 Devil's Dyke TQ257108 No
214 Wilmington Hill TQ548034 Yes
213 Kithurst Hill TQ081125 No
207 Telegraph Hill SU871264 No
214 Willingdon Hill TQ577009 No
200 Detling Hill TQ804586 Yes
200 Newmarket Hill TQ362067 No
188 Cheriton Hill TR197396 Yes
175 North's Seat TQ843119 No
164 Cliffe Hill TQ434107 Yes
155 Bedham Hill TQ014221 No

Littleton Down misses out on being a Marilyn by less than ten metres of relative height, and so qualifies as a 'SubMarilyn'.

Littleton Down

Marilyns were first defined and listed by Alan Dawson in his book The Relative Hills of Britain. This was supplemented by an Update to The Relative Hills of Britain in April 2006. Other hill lists are available from the following websites:


Rules for reaching the summits

In Chapter 2 of his book The Relative Hills of Britain, Alan Dawson notes that anyone contemplating the ascent of all the Marilyns must make some decisions about what are acceptable means of reaching the summits:

It may seem silly to raise ethical questions in an activity as essentially simple as walking, but anyone contemplating the ascent of all the Marilyns must make some decisions about what are acceptable means of reaching the summits. Does a trip on the Snowdon mountain railway and a fifty-yard stroll to the top count as an ascent of Snowdon? Most walkers would say certainly not. But the mainline railway across Rannoch Moor to Corrour Station is usually considered a valid means of access to the remote hills of the Ben Alder area. Everyone uses public roads to reach the start of a walk, but in some places they come very close to the summit of a hill. No-one seriously argues against using these, as the only ethical alternative is to start every walk from sea level, which even the purest of purists would regard as excessively silly. Yet once off a public road any form of motorised transport is likely to be frowned upon by those on foot. The off-road use of man-powered devices is less controversial, but it's a tricky question to decide whether an ascent assisted by skis or mountain bike is as valid as an ascent on foot. Personally I would say it isn't, but I have no intention of laying down rules for valid means of reaching a summit. The only techniques I would definitely outlaw are those that involve landing on or near a summit from the air, so any 'ascents' by helicopter, chair lift, parachute, balloon etc definitely do not count!

My recommendation is to use the list to give some extra purpose and enjoyment to your walking, and to encourage you to visit new areas and see new views, but do not let it dominate your thoughts so much that the bagging of summits blinds you to the character of the countryside. Lists can offer a tremendous incentive to actually go out walking more often, and you'll find that it's almost always worthwhile and enjoyable wherever you go.

Roads come very close to (or even reach) the summit of many of the hills lying to the south of London, but if your pleasure is walking, it seems particularly pointless to drive (or take a bus) to the top, simply to bag the peak. I've therefore devised a set of rules for reaching the summits which are designed to give a decent walk. The rules are:

The last rule, that walks should be at least 16 km long, is guidance. Some hills (Cliffe Hill, for example) naturally suit a shorter walk.

I have devised walks to visit all the hills lying to the south of London, using the rules above. I have written up a few of these walks - details can be found on the Walks page of this site.