By Michael McHugh, PA
Brexit is a worrying "tragedy" forcing people to take sides, Northern Ireland's oldest peace and reconciliation centre has said.
The choice between a hard Irish land border or a soft frontier in the Irish Sea is confronting those who previously did not have to take a position on contentious questions surrounding nationality, the Rev Dr Alex Wimberly from Corrymeela added.
Some commentators have predicted a risk to the peace process from the EU divorce but the assertion is contested.
Since the Good Friday Agreement, people have been able to hold plural identities of British, Irish or Northern Irish, Dr Wimberly said.
"The tragedy of Brexit is that it threatens to force people to choose a side," he added.
He said that choice was most stark in the threat of a hard Irish land border or a soft regulatory boundary on the Irish Sea.
"Instead of being able to be Irish or British or Northern Irish or both, it will force people to be on one side of the line or other or to declare where they feel they belong, whereas before we had the luxury of not having to make such declarations," he said.
"That is worrying."
After so many efforts to support integrated education, 93% of young people in Northern Ireland attend a predominantly Catholic or Protestant school, Mr Wimberly said.
He added that, more generally, people were becoming more tribal and that those in power feared losing their advantages.
"We have seen that human tendency to see the world in categories of us and them, the human tendency to fear what we don't understand, what we don't know," he said.
"There is an increase in fear that we are seeing because those who have been in positions of power are realising that the status quo is not going to last."
By 2066, white people will have become a minority in the UK, he said.
"There is an increased fear of power slipping away in people who have it and you are getting a backlash and a reaction that manifests itself in things like Trumpism, that manifests itself in things like Brexit, into the emerging trend of race-based violence on this island," he added.