Issued under the previous Scottish Executive, GERS 2004/05 estimated a non-oil fiscal deficit for Scotland of £11.2bn. Broadly accepted by most economists, the report was branded a “dodgy financial dossier” by the SNP, who insisted that Scotland was in perennial “chronic surplus”.

Oxford Economic Forecasting published a very similar estimate, for the same year, of a non-oil fiscal deficit of £10.8bn. It too was derided by the nationalists, who claimed that such studies were “offensive” as they were suggesting that “Scots are too stupid to run their own economy”.

But yesterday, the Nationalist Executive released GERS 2007/08, which estimated a non-oil fiscal deficit for Scotland of £11.1bn, barely changed since 2004/05. Even after including an estimated geographical share of North Sea revenues, Scotland’s fiscal deficit was £3.8 billion, representing 2.7% of Scottish GDP compared with a UK fiscal deficit of only 2.4% of GDP.

But spinning the deficit as a surplus by citing only current budget figures (ignoring capital expenditure) John Swinney described the report as a “serious study” and claimed that it showed that political separation could result in “a flourishing and economically successful Scotland”.

Scottish Labour’s spokesman nailed the issue: “You cannot just strip out one form of spending and pretend it did not happen, just to suit your argument. The SNP are playing fantasy economics.”