Paragraph 23 of the political declaration makes it clear that we would
“build and improve on the single customs territory provided for in the Withdrawal Agreement”.
We know what the EU understands that to mean. In good faith and with best endeavours, it understands it to mean a customs union, as Dan Hannan MEP reminded us earlier. So is it not the case that if we negotiate under this agreement, we will either find ourselves trapped indefinitely in the backstop, because the EU is acting “in good faith”, or have to agree a customs union, contrary to our manifesto?