As uncertainty over Brexit continues, what would a hard border mean for Ireland?
Diarmaid Ferriter has written a new book, The Border: The Legacy of a Century of Ango-Irish Politics, which looks at the history and the potential future of the Irish border.
He joined us to discuss the book and explain why Britain cannot be left to solve the problem alone.
Diarmaid says that, while Theresa May has shown she can't be trusted, "at the same time it's not just Westminster's problem, it's very much our problem."
"Ultimately, Brexit is going to impact Ireland more than anybody else."
