INEVITABLE. That is the tone about Scottish independence emanating from this week’s SNP conference, and indeed I have heard the word used often, in public and private, over the last two days.

Party conferences tend to be dismal affairs for those like me with an impartial disposition. They are the times when the worst instincts of politicians go untempered. Conferences are open season on opponents, where no language or accusation goes too far. For that reason, it may be easy to dismiss the use of the word ‘inevitable’.

But I wouldn’t. Its users may very well be correct. Sentiment towards independence in Scotland has ticked up, albeit gradually, since the first referendum in 2014. There have been occasional spikes, such as the Brexit referendum and Boris Johnson’s ascension to Downing Street, where Yes has taken a lead, before settling, but the trend has been a tick, tick, tick, from 45, to 46, to 47, to 48, to 49 and, on Sunday, to 50.

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There are some obvious drivers of this. Brexit cannot be expected to land well in a country in which 62 per cent of people voted to Remain. A decade of Tory government will inevitably take its toll in a country where the Tories are back down to polling numbers in the low 20 per cent region.

And, most importantly of all for the long-term prospects of the independence movement, the wind of demographic change is very much with them. Bluntly, more newly minted 16-year-old voters vote yes, and more dying voters vote no.

So, the feeling of inevitability amongst the SNP hierarchy - and note that it is they who are pushing this rather than ‘ordinary’ members - looks like it has a solid ballast. It is entirely possible that we will look back in five years and say “Yip, the writing was on the wall”.

Or maybe not. There is another side to this story, and it remains to be seen whether the lurking risks for the yes campaign have been fully baked into their thinking.

At the centre of this is the weekend poll showing unionist:nationalist sentiment at 50:50. This was lauded as a breakthrough; the first time a Panelbase poll has recorded such success. It is progress - of that there can be absolutely no doubt. But I am not at all convinced that it is enough. It was not so long ago that ostensibly senior people were briefing the media that they considered 60% pro-independence polling to be the point at which it was safe to agitate for another referendum. They talked of the stars aligning if Brexit turned into a quagmire (tick) and if Boris Johnson became Prime Minister (tick). How many more stars do they need?

I see a requirement, from the nationalists’ perspective, for the polling to be significantly higher, because those lurking risks are real, and they provide a very competitive counterweight to the demographic dividend.

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Despite the polling indicating a perceived stronger economic future inside the EU than inside the UK, it remains a moot point whether economics will again be the Achilles Heel of the Yes campaign. It cannot be downplayed - the fiscal deficit is dismal, the currency question is further spiced by the inevitable debate over whether or not Scotland will have to join the Euro, and the Green-inspired drift to the left is creating an electorally worrying gap between personal tax rates north and south of the border, a gap which is only likely to expand.

Other significant drivers of voter behaviour will undoubtedly be more prevalent this time around. Voters in Scotland have had an election or referendum every year since 2014 with the exception of last year, which despite the lack of a poll was anything but stable. By the time the next referendum comes around, we will have had another two national elections and, presumably, a formal exit from the EU.

Lenin said there are decades when nothing happens, and weeks when decades happen. We are living that, now, and after the UK eventually leaves the EU it is a monumental request of the politically-fatigued Scottish people to plunge themselves into another potentially difficult constitutional negotiation.

And then there is the EU relationship itself, in which so much stock is placed. For what it’s worth, I think that we are in a manufactured state. I say as a Remain voter that much of the Europhilia coursing through Scotland is faux, with no real foundation. It is a knee-jerk response to current turmoil. When we leave, voters’ default assumptions, and the starting point from which they decide which box to cross, will change.

In essence, we will be asking Scottish voters to choose the EU over the UK. We will be asking them to leave a union to which they retain a fair emotional attachment, to join one to which their emotional attachment is unproven, at best. We may even be asking them to authorise the creation of some sort of, albeit probably limited, Scotland-England border checks.

It is the ask of asks. So much so that I find it difficult to see the SNP’s official position being to immediately rejoin the EU. Nicola Sturgeon, on Andrew Marr on Sunday, invoked EFTA as a short-term post-Brexit solution. I expect that will just be the start.