THE blueprint for independence laid out by the SNP’s Growth Commission implies a decade of austerity and public service cuts, the country’s leading economic think tank has said.

In its formal verdict on the Commission’s controversial report, the Institute for Fiscal Studies (IFS) said it suggested public spending even could be lower than in the rest of the UK.

The formal “observation” from the IFS contradicts assurances by Nicola Sturgeon and other senior SNP figures that the proposals would not mean more Tory-style austerity.

The IFS report, which expands a preliminary assessment by associate director David Phillips earlier this month, is likely to fuel divisions among Yes supporters over the Commission.

The Tories urged Ms Sturgeon to admit her plan amounted to ‘austerity max’.

READ MORE: Nicola Sturgeon defends SNP Growth Commission as left-wing backlash grows

The 354-page Commission report, which Ms Sturgeon ordered in 2016 and was published by corporate lobbyist Andrew Wilson last month, has infuriated the Left of the movement.

It proposes a tight rein on public spending in the first decade of independence in order to halve Scotland’s deficit, shadowing UK corporation tax, and keeping the pound.

SNP members are due to debate it over the summer at three internal party assemblies.

The IFS said the report was “an important contribution to the debate” and “commendably” faced up to the challenging financial position in a newly independent Scotland.

Taking the Commission’s proposal to save all North Sea oil revenue and keep public spending 1 per cent below assumed GDP growth of 1.5 per cent, the IFS said the upshot would be growth in public spending held down to 0.5 per cent a year.

The IFS said the report’s numbers “imply at least another decade of the sort of restraint on public spending that Scotland is currently experiencing. If current policy is austerity, then austerity would continue under the Commission’s proposals.

“The ageing of the population - which adds to pressures on the health, social care and state pension budgets - means that keeping to an overall spending increase of just 0.5 per cent a year would likely require cuts to many other public services.

“Unsurprisingly, the Commission does not say where the axe would fall.”

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The IFS also directly challenged the report’s assertion that it was not proposing austerity.

The think tank said it was “inconsistent to claim that these plans do not amount to austerity but the UK government’s current policy does”.

It said that although the UK government had cut total public spending by an average of 0.2 per cent a year in real-terms between 2009/10 and 2016/17, it was now forecast to grow between 2016/17 and 2022/23 by an average of 0.7 per cent.

“The Commission’s proposals for 0.5 per cent increases per year therefore look remarkably like an extension of current policy in the UK: indeed they imply slightly slower real growth in spending than the UK Government is currently implementing.”

The IFS said that the Commission implied a fall in spending on public services of 4 per cent of GDP over the first decade of independence.

However it said a new country would have no choice but to cut its deficit, to avoid ballooning debt and instability.

The IFS said that if GDP growth exceeded 1.5 per cent a year that could improve the situation, boosting taxes and lessening the need for cuts.

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However it said that if Scotland rejoined the EU as part of its plan to boost growth this could cause costly trade barriers with the rest of post-Brexit Britain.

“The Commission’s figures make no allowance for any negative economic impact from such barriers. They could quite easily outweigh the gains from rejoining the EU,” it said.

“More promisingly, the Commission emphasises the role that increasing productivity, labour force participation and the size of the working-age population could all play in boosting economic growth. It makes sensible suggestions in a number of areas, not least in relation to the role immigration can play in counterbalancing an ageing population.

“Such suggestions, when combined with a sober assessment of the weak fiscal position a newly independent Scotland would likely face, and plans for a decade of cuts to public spending as a proportion of GDP to tackle this, make the Commission’s report an important contribution to the debate.”

READ MORE: Former Yes Scotland chair: SNP Growth Commission relied on 'Scottish establishment' for report

Tory MSP Murdo Fraser said: “Nicola Sturgeon wants us to believe that independence would come cost-free. Yet this impartial expert report makes clear it would be austerity max for as long as 18 years.

"That is the staggering price the Nationalists are prepared to pay for their obsession with breaking up the United Kingdom."

Green MSP Patrick Harvie, who attack the Commission’s "right-of-centre economic agenda" at First Minister’s Questions on Thursday, said: “The compelling case for independence will be one which abandons rather than extends austerity economics. Broadening the tax base, to include both corporate profits and asset wealth, will offer a better way forward.”

Scottish LibDem leader Willie Rennie said: “The highly respected IFS agrees that an independent Scotland would have no choice but to impose austerity on public services.

“The SNP’s own Growth Commission is not one of a range of options for an independent Scotland but the hard, cold reality.

“There is no doubt that an independent Scotland would face cuts to public services for at least ten years, would be prone to greater economic volatility like other small countries, could not rely on oil revenues and could not demand control of the pound.

“The positive alternative is to remain in the United Kingdom with a real drive for a liberal, fair and open society.”

An SNP spokesperson said: "The Sustainable Growth Commission is absolutely explicit in its rejection of austerity.

"Instead it proposes real terms spending growth – including an economic stimulus package where necessary – a sharp contrast to the reality of Tory policies being imposed on Scotland. 

"The report has kick-started a serious and welcome debate over Scotland's future, and Westminster parties are clearly rattled by the boost it has given to the independence case.

"The Growth Commission contrasts the clear opportunities of independence with the despair and economic damage of Brexit – and replaces fear with optimism and hope about Scotland’s future.”