Actually, most of their international interlocutors (to wit, the EU, the US administration - rather, Nancy Pelosi - who made clear that if the UK government intended to break the Good Friday Agreement - an international treaty deposited with the UN, - that they could go boil their heads if they thought Congress would agree a post-Brexit trade deal, she phrased it a bit more diplomatically than that, but that is what she meant - and the Irish government) heard the bit where they said (never subsequently denied) that they would break international law. Never mind the moronic qualification.
The idiot - sorry, individual - who let this slip (yes, it was in his talking points, speaking notes) does not appear to have been the sharpest tool in the cutlery drawer, and probably thought that he was being exceedingly subtle, and clever, by finessing things.
He wasn't, as he has shredded the government's international reputation; after all, if you boast that you are going to break international law (as a western democracy?) you lose credibility, moral authority and your word means next to nothing.
From a practical perspective, this means that it will be a lot harder for the UK to conclude trade agreements (and other agreements) post Brexit.