>> reporter: ireland's minister of foreign affairs and trade, charlie flannigan, plays a leading role in the country's brexit negotiations. >> the object of the exercise now must be to ensure that the very close and positive relations between ireland and britain continues, acknowledging of course that leaving the single market, britain has got to suffer some detriment. and we want to ensure that that detriment to the uk is not going to have consequential loss and damage for us here in ireland. >> reporter: which places the issue the border dividing the two countries front and center. >> we are now faced with a situation where we will have an e.u. frontier right across the island of ireland from east to west, a distance of almost 500 kilometers, and we need to ensure that in the context of the new arrangement between the uk and the european union, that invisible border is maintained in so far as it can. >> reporter: the 300 mile border dividing the republic of ireland and northern ireland is seamless now, but it was heavily fortified during the troubles, the 30-year sectarian conflict