Keith is talking as though the Republic hasn't got a dog in this race. It's just ridiculous. The UK UNILATERALLY declaring (not "agreeing," Keith, pur-lease!) that there will be no changes to the border is illegitimate. Fine as an aspiration, invalid as a demand or declaration. The rules are that unless NI is in the customs union there have to be border controls that, under current arrangements, we don't need. That is not a threat. That's the rules. For over four decades the UK has benefited from being in an organisation with that rule. We changed the game by voting leave, not the EU. It's down to us to suggest workarounds, and the EU rejecting those workarounds is not a threat.