Westminster is alienating young Scottish voters
Westminster is alienating young Scottish voters (Reuters)

The last few weeks have arguably been the most heartening period that campaigners for Scottish independence have enjoyed since the early part of 2012.

The most obvious cause for optimism is that three of the last four polls on voting intentions for the referendum have shown the Yes side closing the gap. Ipsos-Mori's poll was the most positive of the lot because, rather than merely showing that previous No voters had drifted back to the 'Don't Know' camp, it actually showed a significant boost for the Yes vote itself.

This was overwhelmingly driven by an extraordinary 31 percent increase in the number of 18-24-year-olds who favour independence.

Analysis of the polls has suggested that this dramatic change of heart by young people can be attributed to the disproportionate effect of Westminster coalition policies, such as welfare cuts, on the under-25s. I must say I'd be slightly cautious about drawing such sweeping conclusions. The figures for 18-24 year olds in the poll were based on the responses of a paltry 61 people, and it's therefore possible that the apparent transformation is largely a mirage caused by normal sampling variations.

However, if there is at least some truth in the idea that one age group has put aside emotional arguments about national identity, and has instead started to base their voting choice for the referendum squarely on the fundamental question of how - and by who - they want to be governed, this could prove to be a hugely alarming development for the No side.

Anti-independence campaigners have always known that there can only really be one answer to the question "Would you rather that the Prime Minister of your country was David Cameron or Alex Salmond?", and that their only hope was to use scare stories to distract voters from thinking about it too much.

They'll have to hope that the apparent new-found immunity of young voters to this tactic doesn't spread to the over-25s.

Unfortunately, however, the plausibility of two of the specific scare stories has also taken a knock over the last month. The persistent suggestion that an independent Scotland might be thrown out of the European Union had already lost much of its potency following the Prime Minister's January announcement of an in/out referendum on British EU membership.

But an equally damaging blow to the No campaign's position has since come from a much more unexpected source. Professor James Crawford, the expert paid by the UK government to pen a report casting doubt on Scotland's prospects for EU membership, told BBC Radio that he in fact regarded the Scottish Government's proposed 18-month timetable for negotiations with Brussels as "realistic".

In other words, even if it is true that Scotland would not automatically inherit EU membership, the country could still expect to enjoy a "through train" of membership as a result of negotiations being concluded in time for independence day.

It's now extremely hard to see a future for the EU scare story. If the No campaign raise it again, it will be easy enough to remind voters that the UK government's own expert sees no reason to assume that Scotland would lose its EU membership even temporarily as a result of independence, while there is every reason to fear that Scotland would be forced into an EU exit as a result of remaining part of the United Kingdom.

Potentially even more devastating for anti-independence campaigners, though, is the loss of the United Kingdom's AAA credit rating for the first time since the late 1970s. Representatives of the London political parties had for some time been fond of issuing dark warnings that an independent Scotland could not be sure of retaining the coveted highest possible credit status.

And yet we are now told by the same politicians that the UK's own downgrade is a trifling matter. It seems that the Scottish electorate ought to conclude that everything they are told to fear about independence will probably happen as part of the UK anyway - and that it doesn't really matter.

This is particularly damaging, of course, because the Conservatives' programme of austerity - so loathed in Scotland - was to a large extent justified by the need to preserve the AAA rating. Voters will be asking themselves if the pain of being part of a larger country governed by a party they did not vote for is worth it. Looking around the world, there are small countries that have better credit ratings than the UK, and large countries that have inferior credit ratings.

The most that can be reasonably said now is that there is no way of knowing if independence would have a positive or negative impact on Scotland's own rating.

So that's two scare stories dispensed with in the space of a month. On that rate of progress, the pro-independence contagion identified by Ipsos-Mori might just be passed on to the older generations faster than we think.

James Kelly is author of the Scottish pro-independence blog, Ssco goes Pop!. Voted one of the UK's top political bloggers, you can hear more from James on Twitter: @JamesKelly