Professor Anthony Staines:

We cannot close the Border. It is not possible so we will have to live with the system we find ourselves in. If we have clear messaging and responsible behaviour on the part of the people involved, we can deal with problems as they arise but there is no way to close the Border between the North and the South and it is most unlikely that it would be possible to close the border between the rest of the United Kingdom and Northern Ireland. I do not see that happening under any circumstance.