April 10 2018: (back row left to right) Jonathan Powell, Lord John Alderdice, Lord David Trimble, Sir Reg Empey, Lord Paul Murphy of Torfaen and (front row left to right) Professor Monica McWilliams, Seamus Mallon, former taoiseach Bertie Ahern, Senator George Mitchell and Gerry Adams, at an event to mark the 20th anniversary of the Good Friday Agreement, at Queen's University in Belfast. Picture by Brian Lawless/PA Wire