IN the controversy of the last week surrounding Sir Nicholas Macpherson, the former permanent secretary of the UK Treasury, one thing that seems to have been overlooked is the fact he is a Scot. You might not be easily able to tell that from the education at Eton and the career as a high-flying Whitehall mandarin. But it is true.

It is easy understand how Nick, as his Old Etonian pals call him, might be reluctant to show his colours seeing that he springs from a family of Highland landlords, the owners of 30,000 acres stretching into the mountains from a sea loch. You can hire a beat of the main river to fish, or rent a holiday cottage, or visit the gardens for a modest fee, though the laird prefers to keep the stalking for his own kith and kin.

Once we can position Nick, it becomes easier to understand why he intervened so forcefully on the No side in the 2014 independence referendum. His was the mind behind Chancellor George Osborne’s warning to Scotland, “if you walk away from the Union, you walk away from the pound”. At the time, Nick was reproached for breaching the rule that civil servants do not intervene directly in current political debates. His answer was that the rule did not hold if the existence of the state was in danger.

Which makes it all the more amazing that, now retired into private life, Nick should have published an article in the Financial Times headed The Case for Scottish Independence looks Stronger post-Brexit. The subhead runs: The decision to leave the EU changes the terms of debate north of the Border. The whole present situation, the piece concludes, gives Scotland a “golden opportunity”.

What is going on here? It helps to remember that, as the top Whitehall mandarin, Nick served without a qualm those polar opposites in policy and personality, Gordon Brown and David Cameron. I dare say either or both of them occasionally asked themselves, “I wonder what Nick really thinks?”. But that is the point with a Whitehall mandarin. Even he himself is not interested in what he really thinks. He is paid to advise all governments with the same degree of expertise and impartiality.

Now that Nick is a private citizen, he is, of course, free to say just what he thinks, though it is obviously hard for him to cast off the ambiguous habits of a lifetime. But I would guess his present personal reasoning is something like this. He has probably always been, like most members of the British establishment, committed to a future in Europe. Appalled at Brexit, he seeks to salvage a remnant from the wreckage. The best he can do is show Scotland how to stay in the EU. At some profound level, this feeling overcomes his former duty to the UK.

Of course, it would be useless to ask him directly about his web of loyalties. We could only expect a labyrinthine answer, framed to elude easy understanding. So look at what he does, not at what he says. He is in effect waving frantically to Scotland to pursue a certain course. “If it can develop a clear and coherent economic strategy ahead of any future referendum,” he writes, “it not only stands a better chance of winning it but will also increase the probability that an independent Scotland inside the EU can hit the ground running.”

Not much doubt there about the legitimacy of a second referendum. And not much doubt it should be the means for Scotland to escape from the UK into Europe. But look at the precondition: nothing there either of Westminster’s sterile and circular arguments about cuts. These are mere shadow-boxing, given that the UK total of public expenditure has remained pretty level for several years. I recall David Cameron and Ed Miliband going at each other hammer and tongs about running a deficit of either £113 billion or £118bn. In the real world, the difference scarcely matters, and all the forecasts from Nick Macpherson’s Treasury turned out wrong anyway. Now, with Brexit, the UK has abandoned its targets altogether.

In that case, what really counts is the “clear and coherent economic strategy”. Nick notes how the UK economy can be expected, over time, to move away from the European economy, which means a Scotland wanting to stay with Europe needs as best it can to move in the opposite direction. This will only really be done with independence. The question of the Scottish currency looms at that point. Nick favours a separate one. It might be a puny wee thing in itself, but it would offer the alternatives of shadowing either sterling or the euro as we shift out of one economic sphere into another.

This does not mean Scotland could be forced to adopt the euro (an unpleasant prospect as things stand). We would first need to fulfil the so-called Maastricht criteria, the conditions for entry to the eurozone. On inflation and interest rates we already fulfil them, but we miss them by a mile on expenditure and borrowing. So be it: for us the question of adopting the euro therefore lies a long way down the line.

We are in good company. Seven of the 12 countries that joined the EU after the collapse of communism in 1989 have yet to adopt the euro. In our case, a similar 30-year timescale is hardly a horrific threat.

Far more important, in Nick’s view and in mine, is that we should set about a programme of economic convergence with our European friends and neighbours, to show them we mean business, to make us more acceptable to them as full members, and to cash in on their undoubted sympathy for Scotland’s plight in being dragged out of the EU against its will. Once on the path of convergence,we will of course be pushed off from time to time, as fresh economic crises arise. That should not stop us constantly proclaiming our determination to stick to the long-term plan.

It will let us cast away the begging-bowl mentality that renders economic arguments with Westminster so futile, and start to think bigger. We need that growth agenda I have called for in earlier columns, an agenda that will make us a normal European country and rather than a rundown suburb of London, a bit scary though too far beyond the M25 for Westminster to worry about. But 400 miles north is where we will be finding our golden opportunity.