The wording of the so-called “backstop” arrangement – which would guarantee no hard border even in a no deal Brexit scenario – is one the main sticking points in EU-UK talks, which Mrs May said have reached an “impasse”.
While EU members may individually want to recognise British goods as compliant, the EU’s customs code imposes more onerous procedures and checks on third-party goods than those member states are subjected to. For example, UK exporters would have to complete, among other forms, a single administrative document, with 54 parts, for each declaration. They would lose access to the new computerised transit system, the IT system that facilitates trade.
This isn’t the EU deciding to be obstreperous or imposing new barriers; it’s a legal thing – or, as Stojanovic put it in a conversation, it’s literally a case of “computer says no”.