evidence: Rockall is an eroded granite volcane that sits some 230 miles west of the Outer Hebrides and measures only 100ft (30 metres) wide and 70ft (21 metres) high above the sea, says the BBC. Over the years, several attempts have been made by adventurers to live on the tiny island but none have succeeded. Rockall gives its name to one of the 31 weather areas around the British Isles, familiar from the Shipping Forecast programme on BBC Radio 4. The UK claimed sovereignty of Rockall in 1955 – sometimes said to be the last action of British colonialism – and made it part of Scotland in 1972. In 2012, the UK government observed: "No other state has disputed our claim to the islet."