Yesterday, our editor wrote about how Nicola Sturgeon seems to be being swept towards a second Scottish independence referendum by events, rather than choice.

Like Gordon Brown in 2007, the First Minister has allowed speculation to reach the point where she lacks an easy escape route – at least, one that isn’t in the gift of her opponents.

So unionists must face the possibility that, for all that reason and current polling suggest it’s not in the SNP’s interests to demand another vote, they will so demand one anyway.

If this happens, it will probably end up being an extraordinary test for Theresa May, as she’ll also be negotiating Brexit and handling the fallout from this week’s Northern Irish elections, where Arlene Foster and the DUP have engineered a blow to (capital-U) Unionism that Sinn Fein haven’t managed since 1998.

Having had a front-row seat to David Cameron’s many, many missteps in the run-up to the 2014 campaign, May will know that the timing of the question is critical. She’ll also know the year the Nationalists are likely to push for: 2019.

This would mean the campaign was run at a time when the Government most deeply embroiled in the Brexit negotiations; when the outcome (and thus, the meaning of a ‘No’ vote) would be most uncertain. It would also allow the SNP to repeat their 2014 trick of simply rolling their referendum campaign on into the subsequent general and Scottish elections scheduled for 2020 and 2021.

So the Prime Minister’s best option seems clear: yes to a referendum, but after Brexit.

Now the SNP will doubtless claim that Westminster exercising its authority over reserved areas in this manner is an outrage and insult to Scotland.

But as Kenny Farquharson points out in the Times (£), the myth that every Scot has an anti-London breaking point, for so long the SNP’s great engine of incremental estrangement, seems to be malfunctioning of late.

Leaving the European Union was, after all, already supposed to have delivered a great upswell of support for independence. Yet (as this site predicted), it didn’t. It seems increasingly likely that the sort of person likely to back ‘Yes’ because Westminster had the temerity to say no to the Nationalists on something are, as Farquharson puts it, “already in the SNP column of the ledger”.

However, there is a tactical downside to this from the Government’s point of view: it gives Sturgeon the out she’s been looking for with her own supporters. Demanding a referendum and being denied one is probably the very best thing for keeping the separatist troops in line at the moment.

It’s been put to me that May should thus offer the Scottish Government a choice: either a referendum after Brexit or one pretty much immediately, as soon as the details can be worked out.

Going now is almost certainly not something Sturgeon wants – it doesn’t give the next ‘Yes’ campaign much time to change any minds or develop a new case – but if she declined it would at least draw the sting from allegations of Westminster stonewalling.

So the thinking goes, anyway. But this is a gamble the Prime Minister is very unlikely to take, and for a very good reason: the next ‘No’ campaign doesn’t exist yet either.

By that I don’t just mean that the next Better Together hasn’t sorted its offices and staffing yet. I mean that the next campaign is probably going to be very, very different to Better Together, and I don’t think anybody has worked out how yet. Unlike on the Nationalist side, where the SNP’s minuscule allies remain minnows, the balance of power within unionism has been completely upended since 2014, as have some of the fundamental assumptions the No side went into that contest with.

In short, Labour are gone. The referendum and general exposed the pitiable state of the party’s Scottish campaigning machine, on which Better Together had planned on relying. The Scottish elections then finally unseated them as the pre-eminent unionist party, and as a consequence they’ve internalised a deep hostility to future cross-party cooperation.

So come ‘indyref2’ Labour will very likely run their own isolated campaign, based around a split-the-difference radicalism nobody wants, and generally be not be much help to anybody. And last year’s European referendum has also finally, belatedly, given Westminster a lesson in the limits of what you can do with a “fact-based”, economic campaign.

Thus the next pro-Britain campaign is going to have to be more Tory. Not only in that it will be primarily funded by Tories and fronted by Tories, but it’s going to need a much stronger heart-based case for the Union too. Rediscovering and developing that case is a task unionists have long neglected, and it can’t happen overnight.

Finally, it goes without saying that the more time Ruth Davidson has to take the SNP’s measure and blood her own troops, particularly her bumper crop of MSPs, the more effective they’ll be as the core of the next ‘No’ campaign. The Prime Minister will very likely, and very sensibly, buy her that time.