Rockall

In 1997 the environmentalist organisation Greenpeace occupied the islet for a short time, calling it Waveland, to protest against oil exploration under the authority of the British. Greenpeace declared the island to be a “new Global State”, and offered citizenship to anyone willing to take their pledge of allegiance. The British Government's response was simply to give them permission to be there, and otherwise ignore them. Indeed, when asked, the Home Office responded that since Rockall was part of the United Kingdom, and since the UK was a free country, Greenpeace were perfectly entitled to be at Rockall. The project continued until 1999, when the company sponsoring it collapsed and the experiment ended.

http://en.wikipedia.org/wiki/Rockall