tanadrin:

dialogue in Enterprise implies the Royal Navy still exists, and thus 1) the UK is still a monarchy (though it no longer includes Northern Ireland), 2) nation-states still have some coherent identity within the United Earth government, 3) there is something for the Royal Navy to do. very odd.

Like to imagine that just like some modern navies use sailing ships to give ensigns an introduction to seafaring, Starfleet just starts you out on a Trafalgar-class sub