Eilis O'Hanlon: Corbyn Labour victory would have colossal implications for Northern Ireland
Until a few days ago the chances of Jeremy Corbyn becoming Prime Minister were roughly equivalent to Sinn Fein councillor Naomi Bailie being asked to switch on the Christmas lights in Bangor this year after taking to Facebook to call the Co Down seaside town a "s***hole".
Now a new poll from YouGov has thrown a spanner in the works by predicting that Tory leader Theresa May could fall short of an overall majority when polling stations close next Thursday night, and that her Labour counterpart might have the numbers to take the reins of a minority Labour-led coalition government.
Sounds implausible, but you never know. Brexit wasn't meant to happen - and it did. Hillary Clinton was supposed to be in the White House - and she isn't.
If Jeremy Corbyn does step through that famous door at 10 Downing Street, the implications for Northern Ireland would be pronounced.
For the first time the UK would have a Prime Minister ideologically wedded to the campaign for Irish unity, presiding over a Cabinet whose Home Secretary once urged the IRA on to "victory" and whose Chancellor of the Exchequer favoured "honouring those people involved in the armed struggle".
Despite plenty of evidence to the contrary, Corbyn insists that he never supported the IRA, and that he only ever wanted talks on a political settlement.
He's right. What he won't now admit is that the negotiations he wanted were on the IRA's terms.
Just weeks after the Enniskillen bombing Corbyn backed a House of Commons motion which said that violence "stems primarily from the British occupation", and urged the Government to "withdraw all its troops".
That wasn't about helping the peace process. It was cheerleading for the IRA's cause.
Such a background is highly unusual for a British Prime Minister, to put it mildly.
The first thing that would happen should he win would be an acceleration of the drive towards a border poll. Corbyn has already indicated that he'd be prepared to concede a similar referendum to Scottish First Minister Nicola Sturgeon in return for SNP support in Westminster, so he's unlikely to hold out against doing the same in Northern Ireland.
That might be no bad thing. Sinn Fein got so excited by the potential of last year's referendum to change the political landscape that it was prepared to collapse the Stormont Assembly as part of a rolling campaign of destabilisation to push for a "Norexit" from the UK.
A border poll reaffirming that the will of Northern Ireland is to remain British could be the cold, hard dose of reality that Sinn Fein needs to remind it that devolution is the only game in town. It's a risky strategy, though.
A divisive and sour campaign on an issue which was supposed to have been put to bed by the Belfast Agreement nearly two decades ago could equally prove a destabilising force, rallying extremists on either side, whilst any return to Corbyn's knee-jerk 32 county rhetoric would naturally leave unionists feeling insecure, provoking a traditional self-defeating siege mentality.
If the British Government is no longer seen as an honest broker, it could fatally threaten future talks on the return of the Executive. Corbyn would certainly get along with Sinn Fein's local leader Michelle O'Neill. They have a lot in common. Both of them share a fondness for attending controversial IRA rallies, for one thing.
But how could there possibly be a healthy working relationship between Arlene Foster and a Prime Minister who cosied up for years to the terrorists who blew up the bus on which she was going to school as a child, and when she has flatly said that he's unfit to be PM?
Foster is aware of her duties as First Minister in waiting, and will no doubt seek to make the best of a bad lot in the event of a Corbyn victory; but events are unpredictable, and could make detente impossible, especially if he offers any encouragement to Sinn Fein's demands for her head on a plate.
The close alliance between London and Dublin would come increasingly under strain. The Irish Government flirted with pro-unity fantasies after the Brexit referendum, but is more interested in preventing a hard border than with getting rid of the border altogether. "Be careful what you wish for" may be the lesson there.
More worryingly, there are scenarios where it's possible to imagine troops returning temporarily to the streets of Northern Ireland, as they did across other parts of the UK last week when the threat level rose to 'critical' after the Manchester bombing. Is Corbyn, who's always shown a distaste for armed shows of strength, at least by legitimate military forces, willing to take that decision? If not, where does that leave us?
Tensions with the armed forces could easily increase.
This isn't some Latin American banana republic. The Army isn't about to stage a coup if there's a Prime Minister hostile to its ethos - though let's not forget there were elements of the British Army allegedly plotting to overthrow the Government of Labour PM Harold Wilson - but PMs need to trust their armed forces, and vice versa. The country has never had a leader before so openly suspicious of the Army's good offices. The PSNI, which is set to lose 238 officers over the next two years as part of ongoing budget cuts, cannot even take comfort from Corbyn's pledge to increase police numbers, because that applies only to England and Wales. Nor is a man whose Chancellor-to-be advocated the disbandment of MI5 until very recently likely to make funding of the security services a top priority.
There are still too many threats from dissident republicans and feuding loyalists to be complacent.
In a part of the UK that relies heavily on the Treasury block grant, the economic impact of a Corbyn premiership cannot be underestimated either. If Tory cuts were painful, imagine how requests for extra resources might go down under a PM who doesn't believe Northern Ireland belongs in the Union at all.
The chances are that Corbyn will not be walking into No 10 any time soon. Most polls show him trailing his Tory rival by some distance.
But if he does stand any chance, he'll need Sinn Fein to take its seats in Westminster in order to get him across the line.
It would be the ultimate irony if Irish republicans were denied the chance to get one of their best comrades and allies into Downing Street because of their own stubborn insistence on abstentionism.