Calls for a border poll for a united Ireland so Northern Ireland can remain in the EU have been rejected by Britain and the Irish government.

But, with a rapidly changing political climate following Britain’s vote to leave the EU, constitutional certainties in Ireland are no longer as firmly fixed as they were last week.

Some international observers predict a break-up of the U.K. in a handful of years. Scotland and Northern Ireland voted to remain in the EU despite populations in England and Wales opting to leave and forcing an overall Brexit vote in the U.K.

Irish Times Northern Ireland editor Gerry Moriarty says that Secretary of State for Northern Ireland Theresa Villiers and DUP First Minister Arlene Foster are probably correct in the short term to dismiss the notion of a border poll on a united Ireland.

But then he quotes prominent personalities, notably veteran diplomat Richard Haass, predicting that in the near future people in part or all of the North will want a united Ireland with Britain out of the EU.

Haass, a former U.S. special envoy for Northern Ireland, said, “In five years there will no longer be a U.K. Scotland will be independent and part of Europe. Less certain but quite possibly all or part of Northern Ireland will join Ireland.”

Moriarty wrote that although Unionists will dismiss Haass’s predictions as “wild, even inflammatory,” they bear serious consideration. He described the diplomat as a “cold, calculating thinker.”

The calls for a border poll have been led by Sinn Fein leaders Gerry Adams and Martin McGuinness.

Read more: Massive support for a united Ireland poll after Brexit

They were rejected this week by outgoing British Prime Minister David Cameron, Villiers and First Secretary Foster, whose DUP was the only major party in Northern Ireland to push for a Leave vote.

Border poll proposals were also rejected by most speakers in the Dail, including Taoiseach Enda Kenny.

He said under the Good Friday Agreement, a border poll can take place if the British northern secretary believes a majority wants to join the Republic.

“There is no such evidence. There are much more serious issues to deal with in the immediate term and that’s where our focus is,” Kenny said.

Minister for Foreign Affairs Charlie Flanagan agreed. “Rather than focus on a border poll, I believe that our immediate strategy should be to sit down with the British government and with the Northern Ireland Executive and to urgently discuss how collectively we are together going to protect the gains of the last decades and to prevent the worst effects of a U.K. departure from the EU,” he said.

There has been a surge for Irish passports from people in Britain and Northern Ireland who have Irish ancestors.

Even DUP MP Ian Paisley junior, who campaigned for a Leave vote, advised, “If you are entitled to a second passport, then take one.”

Foster and Martin McGuinness, the North’s deputy first minister, are to meet Kenny next Monday as the Northern Ireland Executive begins to draw up plans to deal with Britain and Northern Ireland withdrawing from the EU.

Foster said she and McGuinness would meet Kenny in Dublin on to “commence discussions on the nature of our relationship going forward.”

They were also seeking an urgent meeting with Cameron in the coming weeks.

The North’s vote in the Brexit referendum was 56-44 percent in favor of staying in the EU.

Read more: Let’s look at the bright side of Brexit for Ireland