Without Irish unification, a hard Brexit is impossible | Simon Jenkins

Any additional border controls would further isolate the north’s struggling economy. The DUP must fight for a single market and open borders

Is Northern Ireland the poison pill of hard Brexit? The visit of the new Irish prime minister, Leo Varadkar, to Belfast today is remarkable. This is not just for the astonishing sight of a southern politician who believes passionately in gay rights visiting the still conservative north – given how long the south’s reactionary Catholicism has been butt of...