This claim smacks of “Project Fear” and is most curious especially since all the evidence points to us being ready in March 2019.
So why is this so obviously another scam?
Firstly, the so called Irish border question is something of a fiction. Secondly, there is already a border relating to the movement of people between the British Isles and the rest of the EU. Thirdly, there will be a border on the island of Ireland for the movement of goods, as indeed there is now, but it need not seem so. Fourthly, there will be a border between the UK and the EU for the movement of goods but this can easily be facilitated by a combination of technology and practical policy. And finally, all of this can be ready and in place by 2019.
There has been considerable controversy surrounding the continued free movement of people across the border. The arrangements currently pertaining to the UK and the Republic have been in existence by treaty for almost 100 years, giving free movement of people across the common border.
Neither the UK nor the Republic are in the EU Schengen Zone and, as a consequence, people are currently checked at the borders the UK’s borders whether they are travelling within the EU or entering from the rest of the world. They are not currently checked when travelling between the Republic and the UK.
As long as this persists and there is an effective border with respect to the movement of people between the British Isles and both the EU and the rest of the world, there is no reason why, following Brexit, there should not be a continuation of free movement within the British Isles, including within the island of Ireland.
This regime would in no way challenge the border integrity of the EU given that the British Isles would be encapsulated within a border for the purposes of the free movement of people, as it is now. The only impediment to this approach is the intransigence of the EU and the Republic.