We are now hearing that, unless we agree to the EU's terms, the EU will use an extreme interpretation of the Northern Ireland protocol to impose a full-scale trade border down the Irish Sea.

We are being told that the EU will not only impose tariffs on goods moving from Great Britain to Northern Ireland, but that they might actually stop the transport of food products from GB to NI.
Do you have a source for this claim that goes beyond: "We are hearing now ..." or "We are being told that ..."?