FIFTY-TWO per cent support for independence in the new BMG poll, following on from 51% in the recent Opinium poll, is consistent with two competing interpretations of the direction of travel. It’s possible that public opinion has remained stable at around 50-50 for several weeks and that the Yes camp have random sampling variation to thank for being slightly ahead in the two newest polls. But it’s also conceivable that we’re seeing early signs that the Yes vote is genuinely bouncing back slightly after the dip caused by the Salmond inquiry.

One complicating factor is that both BMG and Opinium have just returned to independence polling after a gap of several years, so it’s impossible to judge whether their methodologies are relatively Yes-friendly or No-friendly as compared to the firms that showed No slightly ahead over the last few weeks.

But an interesting straw in the wind from one of those other firms came in the form of the latest instalment of Scotland in Union’s regular series of propaganda polls, conducted by Survation just more than 10 days ago. It asked the usual tricksy question about whether Scotland should leave the United Kingdom – which is not an independence question, but can be used to measure the trend from previous polls that had the same wording.

Fascinatingly, the numbers are almost identical to the Scotland in Union poll in September, which coincided with commanding leads for Yes on the standard independence question. That perhaps lends some support to the theory that Yes may now be moving back into the ascendancy after a ropey spell.

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The BMG figures for the Scottish Parliament election show that the SNP are doing slightly better than in the most recent polls from other firms, but again, a direct comparison cannot be made. Some of the commentary about the poll has attributed great significance to the fact that the SNP are only “just” on course for an overall majority, but it shouldn’t be forgotten that single-party majorities aren’t supposed to happen at all under a proportional representation voting system – and if a party is on course for one, however slender, it’s a sign that they’re doing abnormally well in comparison to almost all parties across the whole of Western Europe.

The real concern is not that the SNP are in any sense underperforming right now, but that the situation could change rapidly during the campaign due to the volatility we’ve seen in public opinion in a number of elections over the last decade. Yes-supporting parties are in combination projected by the poll to win a very healthy 57% of the seats in Holyrood, but even the pro-independence majority may not be invulnerable if the wheels come off.

For now, though, it’s the Unionists who have most to worry about. Both the Conservatives and Labour would suffer significant seat losses on the BMG numbers. And if the Tories had started to feel that their position as the largest opposition party was more secure than before, they’ll have been given pause for thought once again, because they’re just 1% ahead of Labour on the constituency ballot.

They do have a bigger cushion on the more important list ballot, but the problem is that the public seem to have taken a disliking to their new leader – a variety of polls have given Douglas Ross a net negative rating. We saw with Iain Gray in 2011 how a party can go into free fall in the run-up to an election if it has an unconvincing leader who compares unfavourably with a hugely popular SNP First Minister – although admittedly the Tories may be partly insulated from that danger due to the unlikelihood of their own voters switching direct to the SNP.