About half of trade between Northern Ireland and Great Britain goes via Dublin and Holyhead

Obviously, with Brexit under his scheme, there would for outgoing goods have to be customs controls at Holyhead and for incoming goods controls at Dublin.

One reason this route via the Irish Republic (which is remaining in the European Union) is preferred to direct routes, via Larne, Belfast or Warrenpoint, is that it is faster and so more reliable for perishables.

Another is that the food industry in the British Isles is tightly integrated and the big grocery retailers (Tesco, Lidl etc.) have their warehouses near Dublin, only three hours’ sailing from Holyhead and serving a larger market than exists in Northern Ireland.

Perhaps trucks taking this route between Dublin Port and the border could be sealed like those passing through East Germany between Hamburg and West Berlin before 1990, but there would still be red tape, and separate warehousing would be necessary in Northern Ireland.

Inevitably, costs would increase and so food prices would increase too; those handling the red tape would have to be paid; the necessary extra work would not be done by Mr Johnson’s Young Conservative volunteers.

C. J. Woods, Celbridge, Co Kildare