On 9 November 2019, Norfolk climber Liam Chase became the first person to complete all 120 P600s in a single calendar year, starting with Cross Fell on 1 January, and ending with Pen y Fan.

[8][9] British Isles mountain cartographer, Alan Dawson, developer of the Marilyns designation,[a][10] labelled "Majors" as having a prominence of over 2,000 ft (610 m), but no other criteria.

[15] These tables are therefore subject to being revised over time, and should not be amended or updated unless the entire DoBIH data is re-downloaded again.

In 2006, mountain database publisher, Mark Trengove, added a list of seven "Sub–Majors" (to Dawson, Woodall, and de Ferranti's P600 "Majors"), which had a prominence of between 590–600 m (1,940–1,970 ft), and which possibly could become P600s, or Majors, in the future due to any possible discovered "contour uncertainty, rounding error, or map error".

The DoBIH uses the following codes for the various classifications of mountains and hills in the British Isles, which many of the above peaks also fall into:[16][17] Prefixes Suffixes