European leaders have said Northern Ireland could easily rejoin the EU after Brexit if it votes for Irish reunification.
In a move that may anger unionists, diplomats are reportedly preparing to ask the other 27 EU members to endorse the idea at a summit on Saturday.
Although Sinn Fein has campaigned for a “united Ireland” since the establishment of the Irish Free State in 1922, the predominantly Protestant residents of Northern Ireland have remained against it.
This tension led to the militancy of the IRA and the Troubles for three decades before the signing of the Good Friday agreement in 1998.
Under the terms of the agreement both Britain and Ireland are committed to holding a referendum on the subject if there is a popular will for reunification within Northern Ireland.
The theory is that it will be similar to the reunification of East and West Germany after the end of the Cold War in 1990.
The move would prevent the return of a hard border between the two countries – a serious fear among people in Northern Ireland who believe it would increase the risk of violence in the country.
But increased talk of Irish reunification has stoked fears in Westminster about the potential break up of the UK under the stress of Brexit.
Scottish First Minister Nicola Sturgeon has already called for a new independence referendum after the country voted overwhelmingly for Remain.
She argued that the Brexit vote constitutes a “material change” in Scotland’s circumstances within the union – which would justify a fresh vote under the terms of the Edinburgh agreement signed by David Cameron and Alex Salmond in 2014.
The meeting in Brussels will lay out the formal adoption of EU guidelines for exit negotiations with the UK.
The leaders are expected to take tough opening stances on certain issues such as the rights of EU migrants within the UK and the future of Gibraltar as well as Northern Ireland.
The other EU leaders are keen not to appear to go too easy on the UK as it leaves for fear that it may encourage the Eurosceptics in their own countries to push for a referendum.
Irish Taoiseach Enda Kenny has called for a commitment to a “united Ireland” to be included in the final Brexit treaty.
But a UK government source rejected the move for Irish reunification, telling the Financial Times: “Northern Ireland’s constitutional position as part of the UK is based firmly and clearly on the freely given consent of its people. The UK government has consistently upheld the principle of consent regarding Northern Ireland’s future.
“It is clear that the majority of the people of Northern Ireland continue strongly to support the current political settlement, including Northern Ireland’s continuing position within the UK.”
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