The Scottish Government’s decisions on income tax have been very much under the microscope in the last week.

In the run-up to and ever since the advent of devolution in 1999, the power to vary income tax in Scotland has been a hot topic.

For a long time, it was all a bit anticlimactic. No devolved administration used the initial power to vary the basic rate of income tax by up to 3p in the pound in either direction.

However, following the granting of greater powers over the setting of income tax rates and bands, we have since 2017/18 seen the evolution of a significantly different income tax regime in Scotland.

Given the number of people affected by this divergence on income tax from the rest of the UK, it is hardly a surprise that the issue regularly comes under the spotlight.

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Often, the big noise comes, most predictably, from opposition politicians who like to point out that higher earners in Scotland pay substantially more tax than their counterparts elsewhere in the UK.

However, in recent days, we have seen former cabinet secretary for finance Kate Forbes wade into the debate.

Ms Forbes lost out narrowly last year to Humza Yousaf in the race to be First Minister.

Writing in a Highland newsletter, as reported by the Mail on Sunday, she declared: “Continually increasing taxes is ultimately ¬counter-productive over the long term, even if you agree with it ideologically, because it ultimately reduces public revenue.

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“The forecasts for what the Scottish Government will raise through its latest changes to the top tax bands is just over £80 million. That isn’t to be sniffed at. But the forecasts also suggest that they’ll lose £118m that they could have raised because of behavioural change - ¬people leaving or reducing their hours or treating their income differently.”

The £118m forecast to which she refers comes from the Scottish Fiscal Commission, and is for 2024/25.

It was in so many ways a fascinating intervention from Ms Forbes, which not surprisingly commanded many headlines.

She has, of course, been making her views known on quite a few issues since Mr Yousaf became First Minister.

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However, her latest comments in the wake of the December Budget moves to increase income tax for high earners were particularly interesting. Firstly, it was eye-catching how forthright they were, and then there was the fact that they came from someone who is no stranger to having to make the numbers work in a Scottish Budget.

Sensible arguments can surely be advanced for and against what the Scottish Government has done on income tax.

It is right that this matter should be debated.

As observed in my column in The Herald on Friday, the Scottish Government does certainly look to have prioritised areas that will deliver an economic benefit as well as social good.

Take, for example, free university tuition for people in Scotland. If we aspire to increasing high value-added activity, and want all the competitive advantages of having a highly skilled workforce, free university tuition is a key policy. It enables far wider access to higher education, and avoids this opportunity being based on possession of money to pay fees rather than on ability and potential.

Furthermore, the Scottish child payment from the SNP and Scottish Greens is putting money in the pockets of those who have to spend all or the vast bulk of what they have to live, supporting aggregate demand and bolstering the economy.

The EY ITEM Club think-tank has also offered its view on Scottish income tax policy, and its effects, in recent days.

The think-tank declared that “it should be noted that the proposed Scottish income tax increases for 2024/25 will create a further disparity between Scottish and UK taxpayers”.

It added: “A Scottish taxpayer earning £125,000 will pay £5,221 more in Scotland in 2024/25 than they would if working elsewhere in the UK. This may change after the UK Government’s Budget in March, but currently amounts to a fiscal tightening for an estimated 154,000 higher earners in Scotland.”

Ally Scott, EY’s managing partner for Scotland, said: “In what is already a constrained labour market in Scotland, the incremental increases in income tax have created a meaningful tax cross-border divide, which includes a significant number of NHS professionals, senior teachers and other civil servants. This is now a major concern for employers in Scotland looking to retain talent in an already tight skilled labour market.

“If these growth sectors hold the careers of the future for Scotland, then we need an environment that encourages investment and promotes business, not one that creates barriers for growth or impacts competitiveness.”

However, the EY ITEM Club highlights its expectation that “over the longer term, employment prospects will be dampened by weak demographic growth, particularly compared to the rest of the UK”.

It is worth reflecting on this for a moment.

Immigration from European Economic Area countries has for many years played such an important part in boosting Scotland’s growth potential, counteracting the nation’s particular demographic challenges. It should be noted that the UK also has its problems with an ageing population but the demographics are more troublesome in Scotland.

So the loss of free movement of people between the UK and EEA is particularly damaging for Scotland.

Ms Forbes, for her part, highlighted the importance of “a bigger population, through inward migration and retaining our people” to “see the tax base increase”.

An eminently sensible point in a more ideal world. And an aim that should be pursued in any case.

However, the Tory hard Brexit has most definitely ensured the backdrop for such inward migration is far from easy.