FIVE hundreds days.

That is how long Scotland now has to wait until the independence referendum. If it sounds a long time, recall that Alex Salmond won his Holyrood majority more than 700 days ago and has been First Minister for more than 2000 days – while the SNP have been arguing doggedly for independence for almost 80 years. In that context, 500 days is not so very long.

And if the debate is stuck endlessly probing the detail of questions which many people find bewildering, 500 more days seems an unappealing prospect

They are not exactly the cavalry come to the rescue, but, as we report today, a group of academics and economists has now intervened in an increasingly sterile debate with a blueprint for an independent Scotland.

The SNP often nod to the idea of Scotland as another Nordic nation, but the "Common Weal" plan finally puts flesh on it.

Arguing that the UK economic model is broken, this group borrows gleefully from Scandinavia and Germany to paint a big picture of a post-Yes nation in which tax, welfare, finance, industry and democracy are changed using the powers of independence to advance the common good.

Rather than the dry statistical arguments that engage only a minority, it makes the case for independence being a breakthrough moment, the chance to transform society in the way the Attlee government remade the British system in 1945.

It is a vision of a society better off, more productive, more equal and more at ease. And, yes, it is a society which pays more tax – but what did you expect?

It's a vision which deserves to come under proper scrutiny but which nevertheless is a welcome contribution: positive, tangible, wide-ranging, and long overdue. Many will scoff, but it should prompt serious discussion about the kind of society Scots want for themselves and their children.

With time flying past, it is curious that the SNP and Yes Scotland have yet to offer something similar. Indeed, there appears to be some disarray within the Yes camp

Yes Scotland's chairman, Dennis Canavan, last week called for a separate Scottish currency instead of Alex Salmond's sterling zone. It was not a difference in emphasis, but evidence of a fundamental divide on approach: hot-blooded change against tepid continuity.

Another handicap for the SNP is their disjointed pitch to voters, which offers a blizzard of random factoids instead of a lucid overview.

This weekend, Nicola Sturgeon is marking the 500-day milestone with a statement covering the bedroom tax, renewables, life sciences, pensions, food and drink, oil and university. That is not a vision; it's a list.

The Yes campaign needs to take its lead from the ambition shown in the Common Weal plan, and lay out its own vision – fast.