IT’S generally forgotten now, but back in May 2008 the then Scottish Labour leader Wendy Alexander called on the Scottish Government to “bring on” an independence referendum.

Her analysis was simple. The SNP, she said, appeared to be “toying” with the electorate when it came to testing support for independence. “I don’t fear the verdict of the Scottish people,” Ms Alexander told the BBC.

It was an audacious U-turn, but any discomfit it caused the SNP was shortlived. Prime Minister Gordon Brown failed to support the plan to call the Nationalists’ bluff, and (as a result of breaking rules on declaring donations) Alexander resigned a few weeks later.

But had the UK Government actually brought it on, things might have panned out rather differently. After all, what credible argument would the then First Minister Alex Salmond have had against implementing a key element of his 2007 manifesto?

History, meanwhile, repeated itself in early 2012 when David Cameron effectively adopted Alexander’s strategy, saying he’d be prepared to sanction a referendum with certain caveats, ie the question, timing, etc.

At that, however, the then Prime Minister arguably dropped the ball. Cameron casually accepted a very long lead-in period – more than two and a half years – something Nationalist strategists rightly believed would work to their advantage.

Third time round and once again the phrase “bring it on” is in the air. As reports suggested last week, the UK Government is actively thinking about how to respond to a formal request from the Scottish Government for another independence referendum. As a senior source put it, it’s all about ensuring they are “calm and collected” ahead of any negotiations.

They have a few options, none particularly straightforward. One is simply to refuse, confident in the knowledge that around 40 per cent of Scots don’t want another referendum, whereas in 2014 most voters were open to the idea of the question being put. But this, what might be called the Madrid (or Sir Michael Fallon) option, seems unlikely to fly.

Another option is simply agreeing to everything the SNP want. For several months Alex Salmond has been busy generating the general expectation that a second ballot would take place next autumn; he’s spoken of the need for a lead-in period of 16-18 months, the thinking once again being that a long campaign would increase the Yes vote, with Trump’s June visit and problematic Brexit negotiations all strengthening the “choice of two futures” narrative.

But I detect a reluctance among Unionists – Conservative and Labour – to go down this route, the feeling being that they conceded a little too much with the first Edinburgh Agreement back in 2012. A second referendum would require another inter-governmental agreement, which implies compromise, and it seems to me that could see London agreeing to a referendum, but not on the SNP’s preferred timescale.

In other words, they’d “bring it on” – perhaps by the end of this year. Now sure, the Scottish Government would articulate the usual phoney outrage, but what precisely would their objection rest on? If, as some Nationalists have suggested, a later date is necessary so Scots can see what form Brexit takes, then that’s an argument for holding it after March 2019, not late next year. The First Minister, after all, has been quite clear it has to take place within the “Brexit window”.

The SNP obviously can’t be upfront about wanting a longer campaign in order to build support, and the fact that Nationalist rhetoric points to another referendum as soon as possible strengthens the UK Government’s hand in any negotiations. London will also be keen to link a second ballot to Brexit even if the Scottish Government is not, compelling Nicola Sturgeon to set out precisely what an independent Scotland’s relationship with the European Union would look like.

It would obviously be a risky strategy, but it’s a sign that Unionists have learned some of the lessons from 2012-14, when they were arguably outmanoeuvred by the Nationalists. So focused were they on getting a single referendum question (although they might now regret that), they took their eye off the ball when it came to timing and an extension of the franchise to 16 and 17 year olds (a voting group who, according to last week’s BMG poll, now overwhelming support independence).

So that’s unlikely to be the case this time round. This, of course, depends upon the First Minister asking for a fresh Section 30 Order some time soon. There’s speculation this could happen at the SNP spring conference, although she might also make a slightly lesser demand, perhaps asking for the power to hold a referendum when she sees fit. Given that such a request did not form part of the Smith Commission process, the answer from Westminster would likely be no.

What of Unionist tactics beyond timing? Everyone I’ve spoken to expects a second independence referendum to be much nastier than the first, indeed Scottish Secretary David Mundell and Scottish Tory leader Ruth Davidson have already begun framing it in those terms, the former warning it would “set Scot against Scot” and the latter as another “fratricidal conflict”. This seems reasonable. Just imagine if the European referendum was re-run – it’d be far from sweetness and light.

It’s also clear there would be no umbrella Unionist group like last time, no Better Together Mark II, but rather distinct Conservative, Labour and Liberal Democrat campaigns. Last November Ruth Davidson said she would neither put herself forward, nor did she think it “appropriate for any party leader to lead the Union case”. The preference would be for what one senior figure calls “non-Conservative Unionists” to make the case. Quite who that would be is anyone’s guess.

Today at the London School of Economics Ruth Davidson will outline a “fresh” case for the Anglo-Scottish Union in the wake of the Brexit vote, although in a referendum context it would likely emphasise, as before, economic risk, focusing relentlessly upon currency and trade. Above all, Unionists would depict independence as creating even more instability in a big, bad world; in other words, they’ll throw Nationalist critiques of Brexit back at them.

There are several problems with this, not least the fact that balance-sheet arguments may no longer carry the weight they once did, and also the fact that given the Scottish Conservatives have made opposition to another independence referendum their raison d’etre since 2015, it’ll look a bit odd for the British Tories and “UK Government in Scotland” (as it’s now branded) to work with the SNP in making it happen.

But all that’s in the future. If a second independence referendum is about to become a reality, then the “essential ingredient”, as the former Canadian Prime Minister Pierre Trudeau used to say, will be timing.