Hillclimbing in the British Isles differs from the style of hillclimb motorsport events staged in many other parts of the world, in that courses are generally short — mostly under one mile in length — and this means that cars and drivers do not generally cross between British events and the longer hillclimbs found in many other parts of Europe. In Britain and Ireland, hillclimbing is considered a spectator sport, and the most prestigious events, such as those that form part of the British Hill Climb Championship, often attract several thousand enthusiasts to the hills. All the courses in Great Britain are situated on private land, but some events in the Channel Islands and all events in Northern Ireland are held on closed public roads. Track lengths are traditionally quoted in yards: the longest hillclimb course used in the British Championship is Harewood at 1583 yards, and the shortest is Val des Terres at 850 yards. The longest hillclimb currently in use in the British Isles is Cairncastle, located just north of Larne in County Antrim, N.Ireland. Run by Larne Motor Club, It is 1.65 miles long. A notable feature of British and Irish hillclimbing is the very wide variety of vehicles used for competition. Both cars and motorcycles take part in the sport, and in the case of cars these range from almost standard machines with the only modifications being those required on grounds of safety, right through to specially-built single-seater racing cars. Classic and vintage cars are also very popular in hillclimbing. Generally there are separate meetings for cars and bikes, but occasionally both appear at the same event. There is a system of classes which groups cars into broadly similar categories. For example, the classes for "Racing Cars" are divided into those for cars with engine capacities of under 600cc, 600–1100 cc, 1100–1600 cc, 1600–2000 cc and over 2000 cc. The cars in the unlimited capacity class often use engines from, or derived from, Formula One cars, and occasionally F1 cars themselves have competed. Drivers entered for the British Hill Climb Championship may qualify for a "run-off" at the end of each set of class runs, and it is here that BHCC points are scored. It is common for two drivers, often but not always related, to share the same car at a hillclimb. Such entries are known as "dual-driven" cars. Usually drivers considered the slower in such partnerships will make the climb first, before the bulk of the class for which they have been entered. This therefore allows their companions to make their ascent within the same time frame as the competitors, to ensure similar track conditions. Other than this, there is no special consideration for drivers in dual-driven cars, and both drivers count their results individually.
