Kevin Meagher is a former special adviser to Northern Ireland Secretary of State Shaun Woodward.

Northern Ireland was not meant to last this long. That’s the blunt truth of it.

Following partition in 1922, a succession of British statesmen assumed that the passage of time would resolve ‘the Irish question’ and the two jurisdictions – Northern Ireland and the Republic of Ireland – would eventually reunite.

Only they didn’t.

The Unionist-led Stormont regime in Northern Ireland kept a vice-like grip on proceedings and British Members of Parliament were actually forbidden from tabling questions about what was going on there.

So it wasn’t until the Troubles broke out in the late 1960s that the world saw what a squalid little system the Unionists presided over, with sectarianism built into the fabric of the state.

Reginald Maudling, the Conservative minister sent to close Stormont in 1972 after the Bloody Sunday killings (when 13 civil rights demonstrators were shot dead by British soldiers), was said to have remarked: “For God’s sake, bring me a large Scotch. What a bloody awful country.”

So let’s start with the obvious.

Westminster doesn’t understand Northern Ireland and the British people have little affinity with the place. ‘The United Kingdom of Great Britain and Northern Ireland’ is not a partnership of equals.

For a start, Belfast is as near to England as France is. While it’s tiny population of 1.8 million is about a fifth the size of New York City.

Britain would now be quietly delighted if Northern Ireland was reunified with the South.

Indeed, at the time of the Good Friday Agreement back in 1998, Prime Minister Tony Blair promised that if a majority of people in both Northern Ireland and the Republic of Ireland wanted unity and voted for it in a referendum, then the British government would honor the result.

This ‘principle of consent’ leaves Northern Ireland in an antechamber – and it’s only a matter of time before that majority for change is assembled.

It’s worth pointing out that Britain is not so blasé about its sovereignty when it comes to Scotland.

During the 2014 referendum on Scottish independence, British MPs changed their holiday plans to trek up to Scotland and make the case that England and Scotland were ‘better together.’

When, in turn, the same question is put to voters in Northern Ireland, Unionists will find themselves left on their own making the case to maintain the failing status quo.

There will be no armies of British MPs and campaigners making the journey across the Irish Sea, determined to keep Northern Ireland in the UK. There will be an audible sigh of relief that it’s going.

And it’s entirely possible that Scotland goes first.

Sixty-two percent of Scots voted to stay in the European Union in last June’s Brexit referendum, but they are being forced out because the English voted so heavily to leave.

It’s a sore point that has served to reenergize the campaign for an independent Scotland. In fact, JP Morgan has already advised its clients that it expects to see an independent Scotland by 2019, while the Edinburgh government is already making plans for another vote.

If that happens, then pressure for a similar vote on Northern Ireland’s future will be overwhelming.

And while not all Catholics automatically support Irish unity, it is worth noting the last UK Census found that Protestants now only make up 48 percent of the population with Catholics now accounting for 45 percent.

By the time of the next census in 2021, the ‘Protestant Parliament’ that was created in Northern Ireland at partition will be a hollow boast. How will unionists react to being the minority for the first time?

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Then there’s the economics. Northern Ireland makes no sense, economically speaking. It’s too marginal to the British economy and too heavily reliant on government subsidies to survive on its own.

Yet, last year a major report by a team of European academics found that uniting the North with the Republic would be economically beneficial for both, generating tens of billions in extra growth over the first few years. Irish unity makes economic sense.

Like so many former industrial cities, Belfast grapples with deep-seated poverty and unemployment, while the Irish Republic has breezed ahead of Northern Ireland in recent decades, courtesy of its young and highly educated population and the business-friendly policies of successive Irish governments.

That’s why the previous Unionist First Minister, Peter Robinson, pushed so hard for permission to lower business taxes to match the Irish Republic’s rates. The irony of a one-time unionist hardliner arguing for fiscal harmonization with the country he professes to detest was clearly lost on him.

To be fair, he recognized that the Republic has been transformed and is now the dynamic part of the island, thanks, in no small part, to the investments of US companies keen to locate in Ireland to access the European Union’s single market, something the north of Ireland could benefit from if it was part of a single Irish state.

Which leads us to Brexit.

Britain’s vote to quit the European Union accelerates all these other longer-term issues.

Although 56 percent of its people voted to remain in the EU, Northern Ireland, as part of the UK, will, like Scotland, be forced to leave in 2019.

The results will be devastating. Northern Ireland is reliant on £500m [$609m] a year in funding from the EU, while farmers receive another £350m [$462m] in support payments.

All this funding is under threat.

And the British Government is not promising to pick up the tab if it goes. By 2021 or so, Northern Ireland will probably face a financial and political crisis. Brexit means that Irish reunification will shortly become a pressing issue.

That’s because if the border didn’t exist, all that European funding would be kept. The task of joining together two small, neighboring, complimentary jurisdictions that are already working together, slowly and steadily, is the obvious, common sense move.

And with just 6.4 million people on the island of Ireland – North and Republic combined (roughly the size of the State of Indiana) – it is relatively straightforward, administratively speaking, to reunite.

So however way you look at it: History, population change, economics, the impact of Scottish independence or Brexit; Northern Ireland’s days are numbered.

And because all the rational and optimistic arguments are now stacked in favor of Irish reunification, maintaining the failing status quo is a cause for dreamers who cannot explain why a disinterested British public will want to keep spending more and more money on the place in perpetuity.

Make no mistake: We are now in the final few years of Northern Ireland’s existence.

Those who want to see a united Ireland are now the optimists. And we have all the best arguments to make.

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Kevin Meagher was former Special Adviser to the last Labour Government’s Northern Ireland Secretary, Shaun Woodward and author of ‘A United Ireland: Why unification is inevitable and how it will come about,’ published by Biteback.

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