Hmm.
https://en.wikipedia.org/wiki/British_Isles
> The British Isles are a group of islands in the North Atlantic off the north-western coast of continental Europe that consist of the islands of Great Britain, Ireland, the Isle of Man, the Hebrides and over six thousand smaller isles.
Wikipedia disagrees.
Over the years, I've harbored a growing suspicion that the political Venn diagram surrounding the UK and associated entities has reached the point of such complexity that even the natives can't follow it.
(Not that I think that Americans know the US's territorial classification system either, but...)