The former Ulster Unionist leader Mike Nesbitt has suggested that Brexit could be the "biggest own goal" for unionists in the last century if it leads it a united Ireland.
Mr Nesbitt made the comments during an interview on the Think32 podcast, which debates issues surrounding Irish unity.
He said that while he has heard campaigners talk about protecting the rights of those who identify as British in the event of United Ireland, he hasn't heard any reasons put forward as to why nationalists would want unionists in such a state.
"What I haven't got yet is somebody saying 'we want you, as a unionist, in a new united Ireland, and here's why'," he said.
"It's important because growing up it was always 'Brits out', so how has it became 'Brits in'?, and why has it became 'Brits in'?"
I'm also realistic and I do wonder whether Brexit will prove to be the biggest own goal in 100 years from unionists. Mike Nesbitt
The former journalist and broadcaster stressed that "geography is not destiny" and united Ireland is not inevitable, but Brexit has raised questions.
"I'm also realistic and I do wonder whether Brexit will prove to be the biggest own goal in 100 years from unionists," he said.
"I know a lot of the emphasis is on the border and on tariff and on trade, and these things are extremely important and need to be resolved, but the other issue is identity."
"The Belfast Agreement made very clear that we all self-define in identity and we can be British or Irish or both."
Mr Nesbitt, who backed remain in the referendum, said many people in Northern Ireland feel "diminished" because Brexit has denied them their right to feel European.
He said: "I know there are a lot of people who feel they were diminished on 24 June 2016 by that result for Brexit and a lot of them believe that what happened there was that English nationalists came in over their heads and did exactly what the Agreement said couldn’t happen - denied them their sense of being European.
"They feel diminished and the consequence is that the constitutional question is back on the table for the first time in 20 years. Where it leads, nobody knows."
Touching on a potential border poll in the near future, the former Ulster Unionist leader said practical issues such as policing and healthcare in a united Ireland need to be examined and it was up to nationalists to convince him of the benefits of ending partition.
Mr Nesbitt said that if there is going to be a border poll, "don't let it be like Brexit".
"Before there’s a border poll it has to be spelled out in enormous detail and truthfully, unlike Brexit - 'these are the implications should you choose to vote for constitutional change'."
"I have to say I know people of a unionist background who are now thinking the unthinkable and thinking, would I be better off or worse off? (in a united Ireland).