An isolated fin-shaped stack in the Atlantic Ocean, Rockall (the 'Sea-rock of Roaring', Gael: Sgeir Rocail) lies 186 miles (300 km) west of St. Kilda. Rising to 17.1m (56 feet), it is the furthest outlier of the British Isles and gives its name to a Shipping Forecast Area that is bounded to the north by Bailey, northeast by Hebrides, east by Malin and south by Shannon. Geologically, the island comprises unusual peralkaline granite (sometimes referred to as rockallite) and represents the eroded core of a volcano that last erupted around 55 million years ago. Specimens were collected from Rockall early in the 18th C. but detailed examination and description of the rock did not take place until 1897, published in the Transactions of the Royal Irish Academy.
Rockall and its associated reefs have long presented a danger to shipping and may have appeared on charts as early as 1550, but certainly by 1606. Martin Martin (1698) states that the islanders of St. Kilda had to assist French and Spanish sailors who has lost their ship on 'Rokol' in 1686.
The British Navy landed in 1810 and it was surveyed by Captain A.T.E. Vidal of the Royal Navy in 1831. However, it was not until 18th September 1955 that the rock was claimed for Britain, principally to prevent the Soviet Union spying on missile tests. A helicopter from the survey ship HMS Vidal landed a Royal Marine, Sergeant Brian Peel, who planted the Union Jack, attached a plaque and collected biological specimens.
In 1972, the Island of Rockall Act was enacted to strengthen Britain's title and protect against competing claims from other countries. This Act also assigned the rock to Scotland, becoming part of the county of Inverness-shire. It was subsequently transferred to the Western Isles Council. Perhaps the most bizarre landing came in 1974, when two Royal Marines from HMS Tartar took up guard on the island, standing in full dress uniform next to a sentry box. The first detailed topographic map of Rockall, at a scale of 1:100, was published by the Royal Geographical Society in 1975.
British claims to the rock and in particular the surrounding sea-bed suffered when the United Nations Convention on the Law of the Sea (1982), stated "rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf."
This led to several occupations of the rock. Tom McClean, a former SAS soldier lived on the desolate rock for a record 40 days in 1985. This feat of endurance was broken in 1997, when Greenpeace activists remained for 42 days, claiming Rockall as a micro-nation, renaming it Waveland and refuting British rights to explore for oil. In 2014, the rock became home to adventurer Nick Hancock for a period of 45 days, breaking previous occupation records and raising funds for the charity Help for Heroes. During his time there he was able to use GPS surveying methods to establish the exact height of the rock as slightly lower than the previous estimate of 18m (59 feet). He was able to install a fixed permanent survey marker on the summit plateau. An original estimate of 19.2m (63 feet) was lowered when the summit of the rock was removed by the Royal Engineers in 1971 to allow the installation of an automatic navigation light the following year. Greenpeace placed a solar-powered beacon on top of this light in 1997 and returned to upgrade this in 1998, although it was lost to an Atlantic storm two years later.
The British Government had claimed a 200 nautical mile (370-km) exclusive economic zone around Rockall, initially in relation to fishing rights but later to secure potential oil reserves. With ratification of the United Nations Convention by the United Kingdom in 1997, the British Government had to acknowledge that only a 12-mile (22.2-km) territorial limit was sustainable. Formal claims on the area by Iceland and Ireland were joined by those of Denmark and the Faroe Islands.