Henry Hill is a British Conservative and Unionist activist and writer. He is also editor of the non-party website Open Unionism, which can be followed on Twitter here.

This will be the last Red, White and Blue column before the Scottish referendum. Tomorrow night is the big night, the end of what feels like a very, very long road from the SNP’s ‘impossible’ victory in the 2011 Scottish election. It will be an election night like none before.

Yet despite this, or perhaps because of it, the night itself is shrouded in mystery. With a normal general election we politicos have some mental map of the terrain, landmarks to use to gauge the outcome. We know which seats to wait for, what swings to look for, to gauge the outcome. But the referendum is uncharted terrain, with no comparable prior poll on which to base predictions.

Nonetheless, it appears the attempt has been made. A plea for information on Twitter furnished this map, which plots Scotland’s local authorities (which are the counting areas) and provides an estimated time of declaration, the percentage of the population they contain, and an estimation of the way they will vote. These numbers also inform this handy guide to the night.

The person who told me about them warned me they might lean toward ‘Yes’, although he is someone who would want that to be the case. Take them with a pinch of salt, regardless.

Superficially at least the map looks plausible enough. The Borders and the Northern Isles rock solid for the Union, the SNP heartlands in the North East of Scotland firmly in favour of separation. Aside from Dundee, the other city authorities are leaning towards No, albeit not by huge margins, with Edinburgh the least favourable to the nationalist effort.

Take those predictions at face value, and you have the narrative set out in the guide. But whilst I’m not a professional psephologist by any means, and I don’t intend to disparage Credit Suisse’s work, I do spy a potential problem in their methodology.

As I mentioned, there are no comparable elections to base such work off, so Credit Suisse appear to have based their models on the SNP vote in 2012 (the year after their landslide). The potentially critical problem with this method is that the correlation between ‘SNP voter’ and ‘separatist’ is not as close as one might think.

Let’s take those aforementioned SNP heartlands. Hold up a map of the 2010 general election in Scotland to one from the 1980s or even 1992 and you’ll see that many of the seats currently held by the SNP used to be Conservative territory. As Scottish Labour blogger Ian Smart lays out, these are people who often voted against having a Parliament at all, but have subsequently embraced the nationalists as the most likely vehicle to keep Labour out of power in Edinburgh.

Not only are many of these voters unlikely to be well-disposed towards independence at the best of times, but the exigencies of the campaign have forced the sober-suited centrists amongst the SNP leadership to buddy up with two solidly left-wing parties, the Greens and the Scottish Socialists, as well as the wilder elements of the nationalist movement like Jim Sillars.

Worse still, the Yes campaign has been pitching hard at disillusioned working-class voters who until now have been unshakeable in their support for Labour. The prospect of living in the sort of high-tax, high-spend fantasy land that Alex Salmond is offering them will not appeal to the SNP’s non-nationalist support in the Shires.

Thus there are plenty of reasons to suspect that, with the exception of Dundee, the SNP’s heartlands might not be the places that register the strongest support for separation.

But this is not a one-way street, because the aforementioned pitch to disaffected Labour voters shows every sign of having yielded dividends. There is evidence that a substantial chunk of Labour’s working class base has broken ranks to the Yes camp, whether attracted by the SNP’s numerous promises of more spending or a more abstract and romantic attachment to socialism.

This means that, just as we might expect small-c conservative voters who have packed the SNP for elected office shying away from independence, we can also expect to see voters who previously supported Labour taking a chance on separation.

If all that were not enough, there remain a few broader factors to consider. First, turnout in the referendum will be much, much higher than it was in 2012 or perhaps any election in living memory, and we have no historical data to inform an assessment of the likely voting patterns of thousands upon thousands of people who have literally never voted before. Second, the voters who went to the polls in 2012 had not been subjected to a further two years of the independence campaign.

What this all means is that whilst it is certainly possible to make informed guesses about how the different parts of Scotland might vote, there is an extraordinary amount of room for surprises – even before you factor in which way the undecided will swing or whether there is a “quiet No” effect similar to Major’s “quiet Tories” who so misled the pollsters in 1992.

If I had to offer two areas to watch out for on the basis of what I’ve been able to find out, it would be these. First, Scottish Labour’s traditional heartlands in Glasgow and the west, to see if the SNP have managed to make a critical breakthrough into the formerly unionist working class. Second, ex-Tory SNP areas such as Perth & Kinross, Angus, and Moray, to see whether or not the nationalists have managed to translate conventional political success into support for radical change.

That’s it. By my next column we’ll know, one way or the other. I’ve lined up a fresh box of cigarillos, a Union Flag from Monday’s rally, a pizza delivery leaflet and some good company. I’m all set for the most intense television marathon of my life. See you next week.