The smallest island in the United Kingdom (and in the world) - according to
the Guiness Book of Records - is Bishop Rock. It lies at the most
south-westerly part of the United Kingdom. It is one of 1040 islands around
Britain and only has a lighthouse on it. In 1861, the British government set
out the parameters for classifying an island. It was decided that if it was
inhabited, the size was immaterial. However, if it was uninhabited, it had
to be "the summer's pasturage of at least one sheep" - which is
about two acres.