Walking in the United Kingdom the scrambling suddenly becomes much more serious. In Britain, the term "mountaineering" tends to be reserved for technical climbing on mountains, or for serious domestic hillwalking, especially in winter, with additional equipment such as ice axe and crampons, or for routes requiring rock-climbing skills and a rope, such as the traverse of the Cuillin ridge, on the Scottish island of Skye. The British Mountaineering Council provides more information on this topic. Navigation and map-reading are essential hillwalking skills on high ground and mountains, due to the variability of British and Irish weather and the risk of rain, low cloud, fog
Cuillin the summits had no recorded name prior to this period, although names for corries and other features were in existence. Many of the summits are thus named after early climbers such as John MacKenzie (Sgùrr MhicChoinnich), Alexander Nicolson (Sgùrr Alasdair), and Norman Collie (Sgúrr Thormaid). The Cuillin now consists of two estates divided by Glen Sligachan. The hills on the west side of Glen Sligachan (the Black Cuillin) remained the property of Clan MacLeod despite the long history of conflict between them and Clan MacDonald. The earliest formal record of MacLeod ownership was in a land grant from the Crown