How many of us think that unification is no longer a priority and don't really want unification ?

And that means, that in making the decision, the British SoS must be mindful of the potential of a judicial review, and make the decision on clear and unambiguous grounds (that they decide on) which would survive a court challenge. They can't just wake up in the morning and call a border poll because nothing.

Having a discussion on what those clear and unambiguous grounds might be is therefore an appropriate discussion.

A Judiciial Review has no grounds to compel the SoS to reveal or explain his/her reasoning.

Which part of 'He cannot be constrained' is hard to understand?

What law is going to be invoked in a judicial review?

Yes, it does.

Any citizen can take a judicial review against any government/official decision that they believe is irrational or illegal.

In the case of a decision to hold a border poll, say next week, the decision could be challenged on the basis that there is zero evidence that the passage of a border poll is likely, and that the decision of the SoS should be set aside.

https://www.citizensinformation.ie/en/government-in-ireland/how-government-works/standards-and-accountability/judicial-review-public-decisions/

Given that we share a common law system with the UK, the procedures and principles set out in the attached generally apply in that jurisdiction as well.

Essentially, a unionist member of the community would be arguing that the decision is ultra vires, that the SoS has strayed from their powers by making a decision to call a border poll when it was unlikely to pass. How high the threshold to overturn a decision is, is for the courts to decide, but I would assert that if a decision was made tomorrow to hold a border poll based on current available information, the courts would cancel the SoS decision.

In the case of a decision to hold a border poll, say next week, the decision could be challenged on the basis that there is zero evidence that the passage of a border poll is likely, and that the decision of the SoS should be set aside.

And the SoS says it is his/her opinion that it is likely to pass.

The courts have previously said that is ALL the SoS has to do, they cannot be constrained, they can decide as they wish.

So the SoS can say in reply that his/her judgment is not based on polls but other factors.
A Unionist stating they think it is 'unlikely to pass' has no legal weight.

What the SoS can and cannot do is laid down in determinations of the courts. He/She is fully within their rights to call a BP for whatever reason they deem correct. They cannot be constrained by a Unionists view that a successful UI is unlikely or by anything else.
That Unionist is entitled to challenge but wasting money hasn't concerned them before.

Read the verdict in the McCourt case.

You completely misunderstand the court decision. The SoS is not constrained in making his decision, that is clear. He can be irrational, illogical, ideologically driven, whatever in making his decision, but afterwards, if he cannot defend his decision on rational, logical, clear grounds in a judicial review, his decision can be set aside.

As you say yourself, "the SoS can say in reply that his/her judgement is not based on polls but other factors". When it comes to a judicial review, he will have to set out those factors, justify and defend them. Saying he felt it in his waters won't be enough.

The McCourt case was all about setting out constraints in advance, it has zero influence on a post-decision judicial review. A Unionist stating they think it is "unlikely to pass" has no legal weight, but an SoS stating that they think it is "likely to pass" but offers zero evidence of such in a judicial review has no legal weight either.

If you are in court jumping up and down like a demented Burke, the judge can commit you to prison without constraint.

However, having done so, lawyers on your behalf may challenge that judge's decision under judicial review.

https://www.citizensinformation.ie/en/government-in-ireland/how-government-works/standards-and-accountability/judicial-review-public-decisions/

The court said that they did not have to explain or evidence in advance how they would consider their decision.

"In a judicial review, generally the court is not concerned with the merits of the decision but rather with the lawfulness of the decision-making process. This includes reviewing how the decision was made and the fairness of it."

The sentence in bold is key.

There is no written UK constitution.

If they can partition Ireland then they can jettison NI and Scotland too.

Did the Sos exceed his/her powers or remit as laid down?

No he/she didn't, they are not constrained in making the decision, so it cannot be viewed as unfair. A BP is already provided for in the GFA.
The challenger is attempting to constrain.

It works both ways. So if the UK and Irish governments want a poll, it will happen regardless of the views of unionists.

Look, the two governments could do the smart thing. Hold a non-binding referendum only in the North outside of the GFA provisions, there is nothing that prevents that. If it is passed, negotiate the details, and then hold the GFA referendums North and South at the same time on the full set of proposals.

The GFA referendums will not be held until politicians are as close to certain that they will pass, that is why I think a non-binding referendum will happen first.

No British Prime Minister or SoS will want to "do a Cameron" on it. Cameron was the one everyone and their dog blamed for the Brexit poll.

British Prime Ministers and SoS have enough to do, and enjoy a relatively quiet life, without opening 10,000 swarms of bees by introducing a poll leaving open the fragmentation of the UK, have to deal with division of UK national debt, pensions, increased security risks, implications for NATO and defence, increased division in N. Ireland, argument even on minor things like would the St. Patricks Saltire ( currently on the Union Jack representing Ireland) be taken off the Union flag etc.

Would make Brexit look like a walk in the park. Imagine going down in history as by far the worst British Prime Minister ever?

In fairness the cross border institutions are at least a framework for normalisation. Since the Irish Sea customs border there's more all Ireland business interconnecting too.

Who said the SoS would do it on a ‘whim’?

I am saying they will do it after all the back channel work is done and the Irish government have produced a plan.

‘Political expediency’ is one of the reasons the court said they could legitimately call a poll.

The SoS says ‘in my opinion the plan from the Irish government required and deserved to be put before the people and IMO it was likely to succeed’’

Good luck convincing a court that applying a clause in the GFA is ‘unfair’.

You can JR, if you wish, nobody has claimed otherwise, the issue is winning a JR