The delay by a month brings more uncertainty to an already fragile start to a new economic relationship.
Those marking Northern Ireland’s centenary this summer may find themselves pausing to wonder how many anniversaries it has left.
Driven by demographic shifts and accelerated by Brexit, Irish unity is no longer confined to just wishful nationalists, but now recognised as a serious and pressing issue for governments in Belfast, Dublin and London.
“We’re looking at it within years, not decades,” said John O’Dowd, a politician in the Northern Irish Assembly for Sinn Féin, which supports reunification.
“The demographic and political changes that are happening in the north and across the island of Ireland won’t wait decades. There’s a growing conversation and a growing swell of opinion around it.”
Polls suggest that increasing numbers of people in Northern Ireland, which was created in May 1921 after the partition of Ireland, agree.
A recent survey found that a majority favoured holding a referendum on unity within the next five years, with 47 percent currently in favour of remaining in the United Kingdom and 42 percent supporting a united Ireland. Among the under-45s, reunification led by 47 to 46.
Sinn Féin leader Mary Lou McDonald has urged governments in Dublin and London to begin serious preparations for the possibility that Northern Ireland leaves the UK in the near future.
The Good Friday Agreement of 1998, which concluded the Troubles, a decades-long civil conflict that claimed thousands of lives, states that the UK government may call a vote if it believes there is a likelihood that most would choose to leave the union and join a united Ireland.
“I think what the polls are picking up is a shift in enthusiasm for the idea of a united Ireland and a shift in enthusiasm for a referendum,” said Brendan O’Leary, a professor at the University of Pennsylvania who has authored several books on Northern Ireland.
“People believe as a result of Brexit that Northern contentment with the world after the Good Friday Agreement is no longer settled and in addition the UK itself is unstable.”
While most people in England and Wales voted to leave the European Union in the June 2016 referendum, 62 percent in Scotland and 56 percent in Northern Ireland voted to remain in the bloc.
No UK region has been so deeply affected by Brexit as Northern Ireland, whose open border to the neighbouring Republic of Ireland proved the most vexing issue throughout Brexit trade negotiations.
The ultimate compromise was the Northern Ireland Protocol, which in January introduced regulatory and customs checks on imports from the rest of the UK, keeping the North within the EU’s single market and the Irish border free of barriers or checkpoints.
But the new customs arrangements have played havoc with food and parcel deliveries; supermarket shelves have been empty at times and several big British retailers have stopped shipments to Northern Ireland.
The protocol is a “complete disaster”, said Ulster Unionist Party (UUP) leader Steve Aiken, who described growing anger from his constituents, now burdened with unfamiliar paperwork and charges.
Along with the ruling Democratic Unionist Party (DUP), the UUP has vigorously opposed the Protocol and the so-called “sea border”, which it believes has unwillingly pushed northern unionists towards an economically unified island, as well as delivering a boon to the nationalist cause.
“There’s always been a push from people who want to see the British identity on the island of Ireland removed. This is just the latest aspect of it,” said Aiken, who wants politicians to focus on Brexit and the effects of COVID-19, instead of a potentially divisive referendum.
“There are many people who saw Brexit as an opportunity to further try and promote their aims of ripping up the United Kingdom.”
Northern Ireland’s First Minister and DUP leader Arlene Foster has led calls for the protocol to be scrapped or revised as a row between the EU and the UK over its full implementation continues to escalate.
Others have gone further, with several paramilitary outfits recently announcing, via an open letter to the prime ministers of Ireland and the UK, that they were withdrawing from the Good Friday Agreement.
The Loyalist Communities Council, which represents the Ulster Volunteer Force, Ulster Defence Force and the Red Hand Commandos said both governments “will be responsible for the permanent destruction of the agreement” if the protocol is not amended to restore unfettered access for goods and services.
The group rejected any consideration of violence and the desire to avoid conflict is near total, across nationalist and unionist communities.
But the shadow of the Troubles lingers and intercommunal relations remain strained in many areas.
The partition of Northern Ireland in 1921 gave the predominantly unionist Protestant community a two-to-one majority over the Catholic community, which sympathised largely with the nationalist cause.
But the demographics have been steadily changing.
A census to be conducted in March is – for the first time – widely expected to return a small majority for those in Northern Ireland with Catholic heritage.
Younger voters are less likely to subscribe to the nationalist-unionist binary, placing more importance on EU membership, healthcare and social policies.
Sinn Féin, the former political arm of the Irish Republican Army (IRA) paramilitary group, has in recent years burnished its social democratic credentials, riding a wave of anger at poor housing and healthcare to a close second-place finish in last year’s Irish elections.
Its unity pitch foregrounds the benefits for the north’s sluggish economy, promising more investment and employment opportunities to appeal to those outside the traditional nationalist fold.
The UUP and the DUP have proven less adaptable in widening their base, the latter’s backing of Brexit and the UK’s governing Conservative Party now appearing a critical misjudgement.
Alliance, a centrist party that is strongly pro-EU and neutral on the union, has succeeded in attracting many young Protestants and is currently polling just one point behind the DUP ahead of May’s assembly elections.
According to O’Leary, these voters are likely to be pivotal in a referendum. The progress of both Brexit and the Scottish independence movement will be major influences on their thinking.
“Generations under 45 … didn’t want to see Northern Ireland leave the EU and see the Republic as a very different place to what it was under [1950s nationalist prime minister] Eamon de Valera or his successors and predecessors,” he told Al Jazeera.
However, Aiken, whose UUP favoured remaining in the EU, is confident that British identity will ultimately trump pro-European sentiment.
“If it’s a choice between the EU and the United Kingdom, I pick the United Kingdom every time,” he said. “And the majority of people in Northern Ireland will do the same.”
The wording of the Good Friday Agreement offers some ambiguity as to when the British government should call a referendum.
University College London’s Constitution Unit suggests a consistent majority in opinion polls, a nationalist majority within the assembly, or an assembly vote in favour of a united Ireland could all factor. All remain some years away.
For now, the newly-founded Shared Island Unit, an initiative of the Irish government, offers a platform for increased cooperation between Belfast and Dublin on cross-border issues, while civil nationalist groups like Ireland’s Future advocate for inclusive dialogue between all parties.
Sinn Féin’s O’Dowd believes that unionists may in fact find themselves with more influence in a united Ireland, no longer held back by the English nationalists who pulled them out of the EU.
“What has to be learned from the partition of Ireland about 100 years ago is that when you impose solutions on the minority, and when you ignore that minority, it causes trouble,” said O’Dowd.
“So what we have to do is ensure that the minorities on the island are given a place in the shaping of a new era.”