Numenor and the British Empire

[The Squatter of Amon Rûdh]

Good point, while i dont think Numenor was a direct representation of the British Empire it could well be that an island kingdom that ruled 1/4 of the world may have influenced the creation of an island kingdom that ruled a large part of m/e in his fiction.

No it couldn't. Tolkien didn't like the British empire. He based Númenor on the vast island kingdom of Atlantis, as described in two of Plato's dialogues, Timaeus and Criteas. Atlantis was an island continent that ruled territory on both sides of the ocean that bears its name. If nothing else, the manner of Númenor's fall in the Akallabêth is an obvious reference to the earlier myth. The only similarity with Britain is the establishment of a maritime empire, but this is clearly a coincidence.

Not only is Númenor more like Atlantis than Britain, but also Tolkien specifically cites the myth as his inspiration. He refers to Anadûnê as "the great 'Atlantis' isle" and "Númenor-Atlantis" in letter #131, and in letter #154 he says:

The particular 'myth' which lies behind this tale, and the mood both of Men and Elves at this time, is the Downfall of Númenor: a special variety of the Atlantis tradition. That seems to me so fundamental to 'mythical history' - whether it has any kind of basis in real history, pace Saurat and others, is not relevant - that some version of it would have to come in.

Númenor is not even remotely based on the British empire, being a version of the Atlantis myth. Tolkien says so. End of discussion.