Each UK citizen (who does not have another EU nationality) should consider whether they
already have / can obtain citizenship of another EU country through ancestry, marriage or residence.
The crucial concern is that these steps are likely to get harder to take, and people may find
themselves denied documents because they applied after a certain date, even if they did not know
about the need to apply in advance.
The UK has, several times, given more favourable immigration treatment based on people who