> The term "Great Britain" can also refer to the political territory of England, Scotland and Wales, which includes their offshore islands.[12] This territory and Northern Ireland constitute the United Kingdom.[13] The single Kingdom of Great Britain resulted from the 1707 Acts of Union between the kingdoms of England (which at the time incorporated Wales) and Scotland.

Would be a nice thought, but literally nobody means the descendants of the Britons where talking about being British.

If they did, depending upon what that encompasses, then either large swathes of Scotland would be included (Glasgow is a Brythonic name!), or you'd be excluding England from the discussion.

Largely without fail, someone talking about Britain is talking of the island itself, or the current inhabitants.

You're incorrect, so have the obligatory CGP Grey video: https://www.youtube.com/watch?v=rNu8XDBSn10

Thanks for the reference. Unfortunately I can’t edit the comment anymore.

The irony of a comment trying to riff on the usual "Britain isn't England" trope while getting it completely and utterly wrong, is... remarkable. You are GPT and I claim my devalued £1.