IT'S easy to get bogged down with all the graphs, charts and endless tables of statistics but, in the end, the message contained in the latest Government Expenditure and Revenue in Scotland (GERS) report is a simple one: public spending in Scotland vastly outstrips the amount of tax the country raises.

Scotland's deficit in the last financial year was nearly £15billion, the biggest ever in cash terms, as oil revenues slumped by more than half.

More importantly, Scotland was much deeper in the red than the rest of the UK. The deficit was 9.7 per cent of gross domestic product compared with 4.9 per cent across the UK as a whole.

For the first time in 35 years, since the North Sea's black gold started pouring ashore, Scotland contributed less tax per head to the Treasury than the rest of the UK.

Coming a fortnight before 'independence day,' the date set by Alex Salmond for Scotland's formal exit from the UK in the event of a Yes vote 18 months ago, the response of pro-UK politicians was even more scathing than usual.

An independent Scotland, they chorused, would have needed to borrow heavily, cut spending or raise taxes (or all three) from the outset.

Thank goodness, they added, voters were not taken in by an independence prospectus based on wildly optimistic oil forecasts.

They said that with public spending now £1400 per person higher in Scotland than the UK average, the GERS report demonstrated the advantages of being part of the UK.

Predictably, they were accused by some Nationalists of talking Scotland down, of suggesting the country was "too wee, too poor" to go it alone.

Nicola Sturgeon has a more sophisticated take on the annual GERS figures, making the point the figures reflect the state of Scotland's finances as part of the UK.

An independent Scotland, she argues, would have the powers to grow the economy. GERS, therefore, cannot be read as an indicator of how an independent Scotland's finances would look.

She made the point again yesterday, though without identifying measures that might spark the soaring growth required to bring an independent Scotland somewhere into line with the UK's deficit levels.

That is the real challenge posed to the SNP by the GERS figures.

If they are to stage a second referendum and win it anytime soon, they must convince Scots who were not persuaded by their economic arguments in 2014. And they must do so with Scotland's finances in a weaker state compared with the rest of the UK.

As oil revenues continue to fall, Scotland is likely to be £9billion worse off than the rest of the UK this year, according to one analysis, and the situation is not expected to improve in the foreseeable future. That's a huge shortfall to make up, equivalent to about third of the Scottish Government's total spending in a year.

Until the SNP comes up with a clear, compelling plan for improving the state of the country's finances, it's hard to see support for independence rising to a level that would guarantee victory in a second referendum.