Norway and Sweden have “customs checks at the border” while both being part of the Schengen Agreement. I’m not suggesting this is a desirable or unproblematic

Norway and Sweden have “customs checks at the border” while both being part of the Schengen Agreement. I’m not suggesting this is a desirable or unproblematic solution for Northern Ireland, but to claim that it is “not possible” is false. Any free trade agreement between the UK and EU would of course have “EEA-like” clauses to ensure regulatory alignment.