I know that the Republic has done nothing wrong. But neither has the UK. Both the UK and Ireland are perfectly content with no border in Ireland. It is only the EU that is not. If the EU is so protective of its Single market it is incumbent on them to do the protecting. They can do this either by asking the Irish to impose a border on the island or by imposing a border between Ireland an the rest of the EU. It's just as easy to do the latter (probably easier, in fact) as it is to split the UK into two. It's scarcely the fault of the UK that the EU is so insecure that it must protect itself against (what they term) "smuggling" across the Irish border. The UK:Ireland Common Travel Area was established about forty years before the EU's predecessors were even thought of. I would suggest it trumps the EU's Single Market by a country mile and if the EU wants to protect its market it should be compelled to find ways of doing it. In the "real world" into which you suggest my thoughts do not fit, sovereign nations do not see foreign officials installed on their territory, controlling the movement of goods within it. I see no reason why the integrity of the UK should be sacrificed to protect the integrity of the EU.
//If the EU hadn't done what it did the other week, this would not have arisen.//
I think it would. Tales coming from NI ports tell of obstruction to the movement of goods between the GB and NI when those goods have no likelihood of ending up across the border. The Protocol specifically says that such goods should not be subject to delay, inspection or rejection. It is clear that the EU is simply being obstructive. Mrs von der Leyen's action a couple of weeks ago simply provided added impetus and demonstrated that, despite all its bluster over the last four years, the EU has no respect whatsoever for the principle of a borderless Ireland. I discovered the process that should be adopted to trigger A16 in five minutes. Mrs von der Leyen should have done so as well. She might not have triggered it then without even the courtesy of a phone call to either Dublin, Belfast or London. It was no mistake; it was a demonstration of the bullying behaviour the EU exhibits when it feels threatened. More than that, it illustrates quite clearly that a borderless Ireland means not a jot to the Euromaniacs.