Roundtable: Will Brexit endanger the Good Friday Agreement?

Close neighbours – and not always the best of friends. But the UK and Ireland have found a way to get along pretty well in the last 20 years since the Good Friday agreement. Now, that's under threat. The real problem is what the border between north and south will look like after Brexit. Will there be one at all? There isn't right now - but if the UK leaves the customs union, there might have to be - and that brings a host of difficulties.