Britain’s vote to leave the European Union has raised the stakes in the long and divisive dispute over Northern Ireland’s status.
Concerns that Brexit will lead to a hard border with EU member Ireland have reinvigorated Irish nationalism and its dream of a united Ireland free of British influence.
That in turn has unsettled unionists, who back British rule and fear their majority is slipping away in the region of 1.8 million people.
For some people in both communities, the idea of a new, rigid frontier with Ireland stirs painful memories of the British Army watchtowers and checkpoints that peppered the border during decades of sectarian violence that killed thousands.
The struggle between nationalists and unionists over whether Northern Ireland should unite with Ireland or remain part of the United Kingdom plunged the region into 30 years of violence from the late 1960s which saw 3,600 people killed.
A 1998 peace deal created a power-sharing government that has brought peace and relative prosperity, but has failed to heal the sectarian divide that still defines politics here.
In Clones, a border village in Ireland, checkpoints made border-crossing difficult during that time and Donald McDonald had to give up his family business, a textiles shop.
“I would not want to see us to return to this type of place, this type of barrier. For this, sense of hope and trust and relationships had been damaged by political decision of protectionism by the UK,” he said.
A nearby road bridge was closed by the British 76 times during the Troubles, despite the locals removing the barriers again and again.
The authorities are now considering a plan to establish truck checkpoints near here, leaving locals worried.
“I think that people would react in a way that would not be good for neither for the Good Friday Agreement, nor for the people or for the island as a whole,” McDonald said.
In Northern Ireland the unemployment rate was at thirty percent, but today it’s down to just three percent, which is how people want it to stay.
On the border with Ireland Conor Patterson, who works for the chamber of commerce, has been handing out advice to the Brexit-troubled business community.
“This area has a history of violent challenge of the border as it is a barrier to the free movement of goods and people… And we have enough problems in Europe with radical young people – we do not need another problem of radicalisation,” he said.
“The risk is that dissident forces will radicalise people in the community, especially young impressionable people, and they may be attracted to an ideology that would be promote violent challenge of all of this. We do not want to go there – it is too big a threat.”
While the Catholic Sinn Fein party is against Brexit and wants the reunification of the whole of Ireland – British north and Irish south – the Protestant DUP party is pro-Brexit and wants Northern Ireland to stay with the United Kingdom.