Some historic lists have undemanding prominence criteria. A risk with this is that "pimples" in the topography of higher lying areas are included, resulting in less rewarding summits. Therefore, Jim Bloomer and Roddy Urquhart have concluded that the database should have a minimum prominence criterion of 100 metres. In the past, Corbett’s list of Scottish summits with heights of between 2500 and 3000 feet has been praised as "interesting". A key element to the praise of the Corbetts seems to be the strong prominence criterion (~152 m).
However, it is clear that there are wide ranges of prominence and it makes sense to classify peaks into prominence groups (or bands). The 1-2-5 principle provides a good basis for defining prominence groups. One of the pioneering aspects of Munro’s tables in 1891 was Sir Hugh’s distinction between separate mountains and their subsidiary summits. Applying the 1-2-5 principle takes this distinction further by creating a larger number of classes.
For the UK, the authors have proposed prominence groups with thresholds of 100 m, 200 m, 500 m and 1000 m which are named P100, P200, P500 and P1000 respectively.
|Prominence Category||Min criterion||Max Criterion|
|P100||100 m||199 m|
|P200||200 m||499 m|
|P500||500 m||999 m|
|P1000||1 000 m||1 999 m|
The table above gives the criteria, though in practice in the UK, the maximum prominence of a P1000 is Ben Nevis with a prominence of 1344 metres. Note that the peaks also have to meet a summit height criterion of 500 m.
The prominence groups are illustrated above with examples of peaks with a height of 1000 m. The hill symbol is sized to show the minimum criterion and the green arrow indicates the maximum prominence for a given group. A P100 peak would have its key col between 100 and 199 metres below the summit; a P200 peak would have its key col between 200 and 499 metres below the summit, etc. The breakdown of the UK peaks by prominence group is given below:
A mere 3 peaks – Ben Nevis, Carn Eige and Snowdon – comprise the P1000 prominence group. There are 155 P500 peaks. A total of 1564 peaks have a prominence of at least 100 metres and height of 500 metres.