I’M not a deficit denier. Scotland definitely has an annual budget deficit and one that is too large for comfort, even if you take the latest GERS calculation – 7.9% of GDP – with a pinch of salt.

I know this because the UK has a budget deficit and Scotland, like the other UK constituent nations, has to bear a share.

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However, the reason we have this mismatch between public expenditure and tax income goes back to Gordon Brown, who unwisely pumped up borrowing at precisely the moment tax receipts were at their maximum. This meant that as soon as those tax receipts collapsed with the Banking Crash, the deficit was bound to balloon to record levels.

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The notional deficit allocated to Scotland in the GERS figures is just that – notional. Any actual deficit emerging if Scotland was independent would depend on (a) the outcome of the divorce negotiations, and (b) the new domestic taxation regime decided by Holyrood.

Take one example: the new GERS figures show a rise in oil income from £266 million in 2016-17 to £1.3 billion in 2017-18, because the price per barrel has more than doubled.

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This windfall would be even higher but for the fact that the marginal tax rate on oil production has been slashed from around 60% to 40%.

If, say, an independent Holyrood government demanded £10 for every barrel – as was the case in 2010, when oil prices were comparable with today – then the Scottish exchequer would earn circa £6bn in tax revenue. That’s enough to halve the GERS notional deficit at a stroke.

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Certainly, identifiable public spending per head in Scotland is higher than the UK average. But this reflects unique social needs in Scotland and you will find similar disparities in other UK regions. As it is, tax income derived in Scotland is more than enough to pay our revenue expenses, including pensions.

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The true source of Scotland’s current notional deficit arises from our “allocation” of UK overheads, including defence and interest on the national debt. An independent Scotland can find more deficit reduction in those areas.

Also note that, according to GERS, Scottish tax income from stamp duty, capital gains and inheritance tax has fallen sharply relative to the UK average.

Why so? Because the insane London housing market, which is driven often by money laundering from abroad, pours cash into the Treasury coffers.