The latest evidence on earnings across the nations and regions of the UK drew a notably grudging reaction from a government spokesman in Edinburgh. According to the latest annual survey from the Office for National Statistics, median gross earnings in Scotland are now the fourth highest on these islands, still lagging behind London, the south-east and east of England, but ahead of Wales, Northern Ireland and six other English regions. "While the average figures are positive," our Holyrood source conceded, "earnings within Scotland vary greatly between local authorities. For too long our economy has been underperforming to the detriment of Scotland's people."

That second sentence is the standard response we have come to expect from a government which has to have us believe no economic good can ever come to Scotland from within the present political Union. But consider, for a moment, that other point about earnings varying greatly across Scotland's council areas. On these figures, average earnings right across 10 of our local authorities (Aberdeen City, Aberdeenshire, East and South Ayrshire, East Dumbartonshire, East Lothian, East Renfrewshire, Edinburgh, South Lanarkshire and Stirling) are already higher than the east of England average. Three (East Dunbartonshire, East Renfrewshire and Edinburgh) are also ahead of south-east England. Others are close behind.

Clearly, many of Scotland's people are, in comparative terms, already doing quite nicely out of their "underperforming" economy. But it was the next comment from the spokesman that struck me as odd. "The Scottish Government is committed to addressing income inequality to build a wealthier and fairer Scotland," he said. Maybe I haven't been listening, but it's a long time since I heard any politician in power, in either Edinburgh or London, say anything significant about confronting the growing inequalities in income and wealth right across the UK.

At Westminster the first big tax debate of the Brown premiership has been all about inheritance and capital gains tax, with all the concessions made so far - or still demanded by vested interests - likely to widen inequalities, not narrow them. Holyrood has limited fiscal powers, of course. But while the SNP minority government has said plenty about its aspiration to make Scotland the third richest economy in Europe, it has said next to nothing about how it would go about reducing material inequality here in Scotland. Its big tax pledges - to freeze and then abolish council tax, replacing it with a flat 3p rise in basic-rate income tax, while still within the UK; and to slash tax on corporate profits once independent - will do nothing to address the growing wealth and income divides which already characterise modern Scotland.

We may not be talking about wealth transfer to the already rich on the scale that characterises the Bush presidency in the United States. But, be in no doubt, Britain - and Scotland within it - is becoming an increasingly unequal society. Thirty years ago, the most prosperous 1% owned 21% of all the marketable wealth in Britain. In recent years that share has risen as high as 24%. The more prosperous half of the population owns collectively 93% of all the wealth, leaving just 7% for the other half to share.

In the mid-1990s, after a major inquiry, the Joseph Rowntree Foundation concluded that, since the late 1970s, the gap between rich and poor in Britain had widened rapidly. The pace at which inequality had increased was faster than anywhere but New Zealand. Over that period, the hourly wages of the lowest-paid men had actually declined, while the earnings of those at the other end of the scale had grown by 50%.

The arrival of a Labour government in 1997, through the introduction of the minimum wage and tax credits, stemmed that runaway growth in inequality. But these measures, despite all the advance billing, did very little to reverse that trend. According to the Institute for Fiscal Studies, from 1996/97 to 2005/06, the real incomes of the poorest 20% in Britain grew by 2.2% a year, while the incomes of the richest fifth grew by 2%. As Chancellor, Gordon Brown may have been mildly redistributist. But he certainly didn't reverse the runaway growth in inequality which had characterised the Thatcher and, to a lesser extent, the Major years.

And some of the concessions now being made to middle Britain, especially on inheritance tax at UK level and a growing array of universal perks - from free bus travel and personal care for the elderly to plans for free prescriptions and the abolition of the graduate endowment - on offer here in Scotland, are almost certain to reinforce existing inequalities.

I spent some time with representatives of community-based housing associations in Glasgow and the west of Scotland this week. They are concerned that community ownership of housing for rent is being pushed further and further to the fringes of Scottish society. No-one wants to rent a house from a housing association any more, they fear. If they do, it's because they have no other option. Indeed, their seminar was billed: Will the last housing association to leave please switch out the lights.

But hadn't they taken some comfort from the new Scottish Government's housing strategy? After all, it plans to build more houses, to higher standards, across all tenures by the middle of the next decade. Many seem unconvinced. When they hear the Deputy First Minister, Nicola Sturgeon, say: "There has been a fundamental shift in housing aspirations in favour of owner-occupation. Part of government's role is to help people realise that ambition," they instinctively think that means this administration, despite all its protestations to the contrary, isn't really taking demand for social rented housing as seriously as that for owner-occupation.

Then there is Ms Sturgeon's decision to end the right-to-buy for all new social housing built by local authorities and housing associations and to review the right-to-buy existing stock in due course. The right to buy introduced by Mrs Thatcher was almost as reviled as her poll tax in Scotland. But an awful lot of Scots took advantage of it and, in the process, saw a step-change in their relative prosperity. Closing that avenue off now, in the absence of any other coherent programme of action on inequality, could compound the existing gulf between rich and poor.

In his big conversation with the Scottish people, Alex Salmond has had plenty to say about how he intends making Scotland, as a whole, one of the richest places on the planet. But all the per-capita number crunching in the world is meaningless until he tells us an awful lot more about how comfortable he and his party are about existing inequalities in income and wealth across Scotland, and how he plans to confront them.