Scotland’s public spending deficit has reached almost £15 billion, making it proportionately more than twice the size of the UK figure.

Official data released on Wednesday shows that Scotland is in the red to the tune of 9.5 per cent of its GDP, compared to four per cent for the UK as a whole. The figure is understood to be the highest in the EU, after Greece at 7.2 per cent of GDP and Spain at 5.1 per cent.

Meanwhile, Scotland’s illustrative share of North Sea oil revenues - which were central to the SNP’s case for independence in 2014 - plunged from £1.8 billion in 2014-15 to just £60 million last year.

The SNP’s blueprint for separation claimed before the independence referendum in 2014 that oil revenues would be up to £7.9 billion this year, which would have been the first year of separation if there had been a Yes vote.