WHEN Nicola Sturgeon addressed the pinstriped suits of the Institute of Directors in London this week, she told them inequality was one of the basic reasons why a majority of English voters opted for leaving the EU.

Many commentators would agree: There was an obvious revolt against Europe in the poorer regions south of the Border, and especially among those who have in recent years been seduced by the anti-establishment rhetoric of Ukip.

But that hardly explains the differences with Scotland. After all, inequality here is little different in any material degree from inequality in England. We do lack the minority of super-rich who live in the most exclusive parts of central London, and who seldom come into contact with the rest of a local population driven to the suburbs by the house prices.

Take the super-rich out of the equation, and the social structure of Scotland is more or less identical to the social structure of England.

That may be all the more surprising because the First Minister’s championing of equality is nothing new. It has been a prime aim of the SNP ever since it came into government in 2007, fleshed out from 2011 with an elaborate set of targets meant to increase the opportunities, skills and earnings of poorer people. Up til 2013 or so, the measures did seem to be having some effect, with a small but perceptible closing of the gaps in income and wealth.

But that trend has since gone into reverse, and now we are more or less back to square one. With all the economic problems caused by Brexit, and in Scotland by the crash in the oil price on top of that, there would not seem to be much scope for further progress towards equality in the near future. On average we have all got a bit poorer, and nothing on the horizon seems likely to let us get rich quick.

To any student of politics this comes as no great surprise. The past is littered with the records of reforming governments that promised to bring in an earthly paradise, and sometimes even succeeded in clearing the ground for it to be built. But in the long run they all squandered their early enthusiasm, lost the energy to tackle fresh challenges and were finally overwhelmed by unexpected events. The world resumed its accustomed course, and the reforming government could count itself lucky if it had left anything to be remembered by.

The UK of our parents’ or grandparents’ generation offers an example. After 1945, by dint of heroic exertions against daunting odds, the Labour government gave a country exhausted by war the welfare state. In health, education and employment ordinary people saw astonishing advances. But the whole experiment came up against rising problems and by 1979 the English, at least, were ready to turn to a new set of solutions resting on economic liberty rather than on state control.

One interesting thing to note about those 34 years of endeavour is how, all the way through, social equality remained one of the aims, accepted even by the Tories, who in their own lengthy spells of government made no serious attempt to dismantle the welfare state (thereby presenting Mrs Thatcher something to sink her teeth into). But during this collectivist third of a century, how much progress took place towards the more specific and measurable goal of greater equality in incomes?

Overall there was none: The distribution of incomes remained more or less the same in 1979 as it had been in 1945. In relative terms the rich remained just as rich. In relative terms the poor remained just as poor.

It was not as if governments had never tried. In the old days, rates of taxation rose far more steeply then than they do now. At present nobody seriously argues that personal income should be taxed at more than 40 or 50 per cent (the variations are all minor). Under the Labour government of 1974-79, the highest marginal rate of taxation was 98 per cent.

I don’t know how many individuals were ever actually taxed at 98 per cent, but I’m pretty sure it would not have been many. People earning at the necessary level would, after all, have had the money to pay accountants to find ways of relieving them of tax.

This was how the British tax code started its progress towards the 15,000 pages it covers today and how accountancy, previously a profession for harmless drudges, turned into big business. Now, for every loophole the taxman closes, the accountant opens another one. In any event, it is not a system that generates equality.

All this British experience has important lessons for a Scotland considering how to use the powers of taxation just handed down to it. Our new system is a mess, and its incoherence will rule out any rational reform of welfare, for example. No doubt Westminster did that on purpose. But the Scottish Government will be able to raise income tax if it decides to, and to that extent pursue its own agenda of equality.

Without wishing to appear a killjoy, I suspect the Scottish Government may find this pursuit still more fruitless and frustrating than British governments before it.

For a start, we do not have many super-rich. Only 13,000 Scots pay tax at above the standard rate. Never mind about taxation, if you confiscated the entire incomes of such people the yield would barely cover one year’s public spending. Anyway they always have the option of just removing themselves from Scotland, which is what native sons such as Jim McColl and Sean Connery have done even under British rates of tax. I must say I think it would be better for these supporters of independence to be living here rather than in Monaco or the Bahamas.

There is a trail of poor people at the bottom end of the income distribution, but otherwise the great bulk of Scottish workers have earnings within quite a narrow range. The median wage is about £26,000 a year, and you will not find many taking home less than £22,000 or more than £30,000. This may raise, rather weakly, issues of equality, but surely issues of talent, ability, hard work and seniority merit consideration too.

Is it the ideal that a manager should be paid round about the same as his deputy? Should somebody who has worked 30 years for a firm be paid about the same as somebody who has worked there for five years? Should doctors be paid roundabout the same as clerks? And what about footballers? Should we be aiming to squeeze them back towards an average of £26,000 a year? That would certainly spell final doom to the Scottish Premier League – come to think of it, perhaps not a bad thing.

If by equality we mean making life a bit better for the poor, then let us define it as a work of welfare – where there is always room for improvement.

But all this prattle about equality merely confuses the issue, unless one of its supporters can offer a better definition of it than we have just now, with answers to the sort of detailed questions I asked above. Without that, the Scottish Government will set itself goals that can never be met, doubtless with dire consequences for itself and the political status of its country.