> 5. Once free movement has ended from 31 October 2019(1), EU citizens and their family members arriving in the UK will be admitted under UK immigration rules and will require permission (leave to enter or remain). Unlike EU free movement, this will not be a rights-based system so those who do not hold valid immigration permission to be in the UK will be here unlawfully and may be liable to enforcement action. This is a crucial difference between UK immigration law and EU free movement law, which does not require permission from the Home Office for a person to be here lawfully.
So, what happens to an EU national who is ordinarily resident in the UK but has left briefly and is now returning to the UK? What exactly happens at the border? Which documents do they present to guarantee re-entry?
(You quote below the statement that they will be able to show an EU passport, but of course that does not constitute "valid immigration permission to be in the UK")