But a quarter century on, such a scenario still looks remote and remains controversial.

- What does the accord stipulate? -

Under the Good Friday Agreement, the UK and Irish governments "recognise the legitimacy of whatever choice is freely exercised by a majority of the people of Northern Ireland" over its status.

It could be a continued "union with Great Britain or a sovereign united Ireland," the deal adds.

The late 1990s pact also notes that "the present wish of a majority of the people of Northern Ireland" is to remain part of the UK.

It goes on to say that "if in the future, the people of the island of Ireland exercise their right of self-determination... to bring about a united Ireland", both governments are obliged to legislate "to give effect to that wish".

The British province would be integrated into the Republic of Ireland -- a European Union member -- if its population also consents to the constitutional change in its own referendum.

- What do referendum backers say? -

Queen's University Belfast law professor Colin Harvey -- a board member of Ireland's Future, which campaigns for "new constitutional arrangements on the island" -- admits the conditions have not yet been met for a poll.

"Not tomorrow... not even next year," he tells AFP.

But he argues it will happen, "perhaps in the next decade or 15 years".

Harvey is busy producing policy documents and papers to map out a way forward to ensure a "stable, responsible transition".

He concedes such a vote will divide the population, but notes "democracy is divisive" by its nature.

"We would be dishonouring their memory if we avoided this discussion about the constitutional future," he adds of the "courageous peacemakers" behind the accords.

"We should face into that, as difficult as it may be."

- The opponents' view? -

Some on the island push back against the very idea of holding a so-called border poll.

"There is no basis to call it," says Trevor Ringland, a Belfast-born former Ireland rugby player and now a lawyer who works to build bridges across sectarian lines.

The son of a Northern Irish policeman, he notes the province used to be "one of the most dangerous places in the world" to have such a job.

He believes a referendum would be "a setback", arguing economic progress and social changes over the past 25 years have reshaped Northern Ireland.

Its young people now define themselves less by religion and mix more with different communities, according to Ringland.

"Demographics are far more complex than being simply divided by one religion or another, or by one simple identity -- I'm British and I'm also very much Irish," he says.

"We have a real opportunity here to make sure what happened never happens again."