'NOTHING has changed and nothing probably will change," a senior Coalition source noted the other day about the state of play in the referendum stakes.

To put it another way, Scots have not in the past been convinced by Alex Salmond's vision of a bright, shiny independent Scotland, are not being convinced and will not be convinced by September 18.

In parallel, one of Ed Miliband's loyal lieutenants said people were still waiting, and waiting, for the SNP's "game-changer" moment, which despite the White Paper had failed to materialise. "Will it ever emerge?" he asked.

There certainly remains a lively spring in the UK Government's step. It believes its "steady as she goes" strategy is working with opinion polls continuing, generally, to show a healthy lead for the Union. But this strong confidence in the corridors of Whitehall appears much brittler within the tearooms of Westminster.

The latest string of polls has shown a slow upward trend towards a Yes vote. Indeed, the most recent snapshot put the Yes-No difference at 37% to 44%; in September it was 32% to 49%. In other words, a 17 point lead has slumped to just seven in six months.

Of course, taking one poll to make a firm conclusion is a mug's game. But the narrowing of the polls will become significant if it continues; it is a big if.

This week, Westminster sources detected a definite "wobble" within Tory ranks about what was happening north of the Border.

This was despite the fact that the intervention from Mark Carney, the Bank of England Governor, was generally regarded as positive for the pro-Union cause.

Now while he may not have said anything particularly revelatory, the fact that such a highly regarded and dispassionate figure actually said it, and talked of an independent Scotland giving up monetary power to London, could only have sown more doubt about the First Minister's professed certainties about an independent Scotland.

It is the Don't-Knows whom the SNP is pinning its hopes on for a late 2011-style surge. One of Mr Salmond's Praetorian Guard suggested the brigade of doubters was as high as 40% of the electorate. He based his experience on doorstep canvassing - not wishful thinking. He dismissed the notion, proferred by one of David Cameron's trusted outriders, that while the Don't-Knows in opinion polls range from 20% to 30%, most privately have already made up their minds (for the Union) and all the politicking thus far, and between now and polling day, will simply reinforce their own privately held views.

Both, of course, cannot be right.

But if the senior Coalition insider mentioned at the start is right that the ballot on Referendum Day - after all the claims and counterclaims, the slog of campaigning, the endless constitutional debates, the policy announcements, the passion, the scaremongering, the exaggerations and all the money spent - produces the same result as most opinion polls predicted at the beginning of the process, some people might look to the heavens and ask: what on earth has been the point?