A discussion panel at the Beyond Brexit: The Future of Ireland conference at the Waterfront Hall in Belfast on January 26

I wrote this in November 2014, 19 months before the EU referendum: "When you scratch the surface of even the most laid-back and agnostic, when it comes to identity, they do have an opinion on the constitution. It's what I call the 'border poll moment': how will you vote when that poll comes (and I still think it will be sooner than most people imagine)?"

Senior figures across unionism told me that it was nonsense to mention a poll, most of them adding a variation of "the sort of circumstances in which a poll would even be considered as a possibility are not happening any time soon".

Today, the border poll issue is rarely away from the headlines. A recent conference at the Waterfront Hall - attended by the broadest swathe of nationalism (from both sides of the border) in my lifetime - indicated huge support for Irish unity, along with the need for an agreed strategy to promote and deliver it as soon as possible.

The unity question has already been discussed within Theresa May's Cabinet, with reference to LucidTalk's opinion poll research on the impact of various Brexit options.

A number of media sources reported last weekend that three Cabinet ministers had suggested that an early border poll would be necessary in the event of a hard Brexit, or a no-deal withdrawal.

Responding to a question from Sinn Fein's Mary Lou McDonald about when a border poll would be called, a spokesman for the Prime Minister said: "The conditions for a border poll are set out in the Belfast Agreement. It remains the Northern Ireland Secretary's view that the majority of the people in Northern Ireland continue to support the current political settlement and that the circumstances requiring a border poll are not satisfied."

Here's the key part of those conditions: "The Secretary of State shall exercise the power (to hold a poll) if at any time it appears likely to him (sic) that a majority of those voting would express a wish that Northern Ireland should cease to be part of the United Kingdom..."

Of course, the word 'likely' is a classic example of the constructive ambiguity which lies at the heart of the Belfast Agreement: in other words, it is open to a number of possible interpretations.

Let's take a number of 'for examples' into consideration: unionists no longer have a majority in the Assembly (for the first time since 1921); in the local government elections in 2014, the Assembly elections in 2016 and 2017 and the general elections in 2015 and 2017, the total unambiguously 'unionist' vote averaged at just below 50%; opinion poll evidence suggests a significant shift towards support for Irish unity in the event of a hard Brexit/hard border/no-deal outcome; we have entered the third year without an Assembly/Executive and there seems little likelihood of a reboot anytime soon; and, crucially, nationalism now seems to be moving beyond the Assembly and an internal power-sharing arrangement to underpin stability in Northern Ireland.

Add all those 'for examples' together and you reach a point at which a Secretary of State could, quite reasonably, concede that the chances of a border poll resulting in a victory for Irish unity - albeit by a very thin margin - certainly falls into the space between possible and likely.

The days when the unionist vote was well into the high 50s in percentage terms have gone. That doesn't mean they would, necessarily, lose a border poll (personally, I don't think they would at this juncture), but it does mean that they need to take a very close look at the figures and work out how to build the pro-Union vote. Just in case.

A border poll would, like the 1998 referendum, push the turnout up very considerably. But no one can say with any great certainty were those extra votes would go.

Neither the pro-Union nor pro-unity side can bank any of them in their own camp. The variables will be enormous, particularly in the event of a hard Brexit.

Would the British and Irish Governments take a position and choose to lobby for the respective camps? To be honest, I don't see how the Irish Government could be neutral during a border poll which, if it resulted in a majority vote in favour of a united Ireland, would present it with enormous political, constitutional, economic and governance challenges.

It would hardly just shrug its shoulders and say, "Ah well, let's just see how the poll goes before we do anything".

It's worth bearing in mind, too, that the response of the Irish Government would be a crucial factor in any call an Northern Ireland Secretary of State would make.

If the Irish don't think they're ready for unity (and, as I say, it would be a huge challenge and problem for them) and aren't convinced that there would be a reasonably convincing majority for it (they really don't want to deal with a wafer-thin victory), then they will - very quietly, of course - let the UK Government know.

I've thought for some time now (although I think the 2014 article was the first time I wrote about it) that a border poll was more likely than not. It is not inevitable and the chances of it happening will lessen if there is a soft landing for Brexit and a Lazarus-like recovery for the Assembly.

That said, circumstances have forced the issue to the top of the agenda for nationalists in Northern Ireland.

And let's not forget the important fact that the solidly pro-Remain 'small-n' nationalists and 'small-u' unionists now seem much more willing to listen to a well-made case for Irish unity.

Unionists do not need to panic. But only a very stupid unionist would dismiss the possibility of a border poll, and further dismiss the possibility of losing it, if one were called.

Very few unionists predicted a victory for Leave in 2016 and the consequent problems we now face. Very few unionists predicted losing the majority in the Assembly in 2017.

Very few unionists predicted the huge mess that the RHI saga would dump upon the DUP's doorstep. Very few unionists predicted the collapse of the Assembly and the rise of post-Assembly nationalism.

Putting it bluntly, unionists should take nothing for granted. Anything and everything could be in play. And that means they need to be prepared for all eventualities.

Personally, I'm sick to death of flag-waving and worn-out mantra-chanting, rather than thought-through strategies, solid deconstruction of pro-unity arguments and a coherent narrative to attract the tens of thousands of extra voters who will turn out if there is a border poll.

Panic isn't required; preparation for all eventualities is.

Belfast Telegraph