The net effects of all of this on the deficit are complex and, at this stage, uncertain. Nevertheless, it is very likely that the different factors affecting the public finances at the current time will be – in relative terms – ‘better’ for Scotland than the UK as a whole.

In short, the key beneficial public finance effects – oil and gas revenues – will be concentrated in Scotland, whereas the costs – such as higher spending or the effects of a recession – are spread across the UK as a whole.

The Institute for Fiscal Studies (IFS) estimates that oil and gas revenues would need to total around £14.5 billion this year for the Scottish implicit deficit to match that of the UK as a whole. They conclude that ‘such a figure is plausible, and may be exceeded’.

This may well change the context of debate around Scottish independence and be more favourable to the ‘Yes’ campaign.

But it is important to note that the long-term trend for oil and gas revenues is for a phased decline. Oil and gas production peaked in 1999 and remaining reserves are now in more challenging and costly areas of the North Sea.

At the same time, governments – including the Scottish government, in which the Green Party holds two ministerial positions – are committed to the transition from fossil fuels to renewable forms of energy, with the objective of reaching net-zero carbon emissions.

Want to see more SNP fails? – Politics Matters