Scotland - Better or worse off alone?

Is the SNP asking Scotland's voters to back a future with higher taxes and fewer public services?

Ahead of the Scottish government's own plans for tax and spending which will be outlined tomorrow, that is, according to the well respected Insitute for Fiscal Studies, precisely what Scots would be looking at if they signed up to going it alone.

Like all of these kinds of studies the IFS has had to make assumptions before being able to do its sums. They assume that Scotland would take on a share of the UK's national debt in line will its population when it became independent.

They use the Office for Budget Responsibility's projections that oil revenue will continue its decline. The researchers also assume that the demographics of Scotland mean the population will proportionately age faster.

Yet even bearing all of that in mind, the results are pretty challenging for those arguing the case for independence.

The IFS warns that an independent Scotland would have an extremely significant black hole in its books for decades to come, with national debt topping 100 percent of national income.

To have any chance of stable and sustainable income therefore, the IFS calculates the Scottish administration would have to make cuts way deeper than the UK government - 8% in public services, or by increasing income tax by 9% or VAT by 8%.

More cuts, fewer services - not exactly a winning formula, and very different from the SNP's current political message.

Clearly none of these are politically tempting choices. And those assumptions, according to the IFS, are based on what they describe as 'optimistic' scenarios - not very optimistic for the SNP.

The debate around the numbers is intensely charged, and difficult, because even extremely well informed estimates of what an independent economy would look like are still just that, estimates.

But as the SNP prepares to reveal its own version of economic events, this verdict from an independent organisation has made it harder for the Nationalists to answer the fundamental question many voters want to know - will they be better or worse off in an independent Scotland?