We all want relations between Scotland and England to remain harmonious, but the First Minister has just himself raised an issue that can hardly fail to cause friction whatever happens on 18 September next year.
During his visit to China, Alex Salmond took up the case of two Chinese teachers in Scotland who had returned home for a break and then been banned from returning to their jobs here.
It seems typical of the sort of arbitrary injustice bound to crop up as the British government tightens controls at the borders in a political panic over the rise of Ukip and, it seems, over a more general resurgence of anti-immigrant feeling in electorally sensitive parts of England.
According to Salmond, Scotland wants no part of it. We are not afflicted with Ukip. We want the friendliest possible relations with China – including instruction of our children in Mandarin by native speakers – so that our exports to the world’s biggest market can burgeon in German style rather than flag in British style.
Above all, we do not want inoffensive individuals to be oppressed by capricious bureaucracy. That kind of thing happens in big countries, but a small country should be able to do better by its citizens, or indeed by its foreign residents and visitors.
Beneath these debating points lies the basic fact that in the matter of immigration there is clear blue water between the public opinion of Scotland and of England.
England has received millions of immigrants in the last half-century or so, first from the Commonwealth, then from Europe and now from more exotic locations. They used to be legal, but today many are illegal. At the borders, others clamour to get in. Whole areas of English cities are populated by these groups rather than by the natives.
There are often tensions, sometimes violent tensions. England appears to have decided it has had enough.
In Scotland we have had immigration, but on nothing like the English scale. In England one in seven of the population is now an immigrant, in Scotland one in 250. These people seem less of a menacing threat, more an enriching thread in the national tapestry, whether as Indian restaurateurs or Polish plumbers.
It would be going too far to say there are no tensions at all, but they are not such as to disturb the public peace. Signals of something deeply wrong, such as the numbers from ethnic minorities in prison or the poor performance of their children in school, are absent.
As a result, public and private attitudes to immigration as between Scotland and England have clearly diverged. The people who survey these things often remark on the fact that Scots people and English people show a similar outlook on life in many of the big questions (though not on the question of social equality and what we should do about it). But here is a specific issue: the Scots are on the whole relaxed about immigration, while the English are not.
This might seem a mere curiosity, but has wider implications. Though relatively little notice is taken of it, migration remains one of the key economic indicators of the modern world. Even amid globalisation, many countries have difficulty exporting their goods, sometimes because of internal problems, sometimes because of external barriers. A country that cannot export its goods will export its people instead. Hence the ceaseless waves of migrants out from the misery of sub-Saharan Africa and from all the countries in chaos round the Middle East or, in the New World, from the grinding poverty of Latin America.
There are implications for the host countries as well. The countries that attract immigrants are successful countries. Their economies are expanding and they need more hands to put to work, more than can be supplied by their own people.
It may seem surprising how this has held true of European countries such as the UK, Germany and France even during the great recession of the last few years. Each of these now has several million immigrant workers, presumably because life in the new home is for all its problems still better than life in the old home.
It may seem equally surprising that the European countries are, to varying degrees, unhappy with the experience. They should not be. It means they can afford to support their aging populations while younger and stronger migrants perform all the hard graft in the most menial jobs. Migrant labour is what has kept their economies ticking over in the hard times, and at a cost to the wage bill lower than would otherwise be the case as recovery gathers pace. All this is reasonably well understood, at least in the US. It has its racial problems, heaven knows, but is conscious of itself as a nation of migrants – and still lifts the lamp beside the golden door.
Where does Scotland fit into the global picture? We have had no waves of immigration, but, on the contrary, waves of emigration: in economic terms just another symptom of our underperformance. That picture has started to improve, but there is still a long way to go and perhaps a different constitutional order is needed to cover the distance.
But the bigger test may be a social one. The latest estimates show Scotland’s population rising quite steeply over the next quarter of a century, from 5.2 million today to nearly 5.8 million in 2037. Immigrants will make up almost 400,000 of that increase.
Luckily, the immigrants who are living here today have not clustered in ghettoes, one of the main causes of the social problems in other countries, not least in England. Once in ghettoes, people find it hard to get out of them, or out of the deprivations that go with them. We should give every encouragement for newcomers to Scotland to integrate in every part of the nation and at all its levels. It will be a test of our vaunted tolerance, but the Pakistani chip-shops of Stornoway set an excellent example.
The offer of national independence usually comes with assurances that in point of fact nothing is going to change all that much. I would myself prefer something a bit more exciting in a country of so many stale ideas and so much dead wood. A new, prospering Scotland would certainly attract more immigrants than we have been used to, possibly with big effects on the inner cities and more widely on a culture that can be complacent and defensive at once. And some of these immigrants may be on their way to England anyway: but that is an English problem.
We might draw reassurance from the fact that the Scots have themselves long been a migrant race, and have on the whole exerted a benign effect on the new nations they enriched.