THE basic trouble is that each fresh move in the complex political games going on at the moment brings further division. So to call amid this turmoil for unity seems to be merely spitting in the wind.

All the same, that was the best the Prime Minister could do during her visit to Scotland yesterday – before Holyrood votes today to request powers under Section 30 for a fresh referendum, and before the British Government sends its letter to Brussels tomorrow announcing its intention to leave the EU.

In each of these acts lie the seeds not of unity but of further division. Holyrood’s request will be ignored for the time being, we are assured from on high. But that must increase over time the pressure for a second referendum, either when the terms of Brexit are known in 2019, or else after 2021 when it is getting bedded in. It is hard to see how the Scottish Parliament can take kindly to the spurning of its majority’s will in the short term. In the longer term, the lesson of its impotence will be rubbed in.

For example, Holyrood will only be able to look on as the British Government sets out to cut the numbers of immigrant workers. These workers are actually also needed in many sectors of the English economy, while being absolutely vital to Scotland if we are ever to grow our economy faster and give a better standard of living to our people, native and immigrant alike. Many citizens of England hate and reject immigration, while many citizens of Scotland see its usefulness and welcome it – especially if it fulfils a humanitarian purpose, too.

Where is the chance in all this of British unity on immigration, among many other questions? Vital interests are at stake: Scotland and England are entitled to differ, as much in practical action as in the expression of opinion. Yet Theresa May has shown in the past that, if Scotland and England differ, then for her it is English opinion that must prevail. This is her definition of unity.

In a 10-minute speech at East Kilbride, brought to an end without allowing time for questions, May spoke of British unity as if it had yet to be deeply challenged, with disunity as a danger palpable enough yet hardly imminent. This was why she ran a Government “never allowing our Union to become looser and weaker, or our people to drift apart”.

But the fact is that the Union has been getting looser and weaker for more than a third of a century, ever since the devolution referendum of 1979. After a Scottish Parliament was restored in 1999, in the teeth of Tory opposition, it took only two terms before it voted in an SNP government, which then gained an absolute majority for the fourth term. It would be going far to regard this as a period of unsullied British unity somewhat distantly at risk.

Why has the loosening and weakening of the Union taken place? There are many reasons, but one big one was certainly the obstinate refusal of the Westminster parties to take seriously any Scottish deviation from the norms of English opinion. In the case of nuclear weapons, of the poll tax and a host of lesser matters, British governments remained determined never to allow “our people to drift apart”. The wilful blindness only made sure of the drift.

We have a further example faced by May, even before the Brexit negotiations get under way. One result will be the end in the UK of the operations of the Common Agricultural Policy, which in itself will be no bad thing. It will also entail the return of the powers over agriculture which before EU entry in 1973, and indeed through the whole 20th century to that point, had been exercised by the Scottish Secretary. But in May’s view, apparently, there is no need to go back to this fuddy-duddy old arrangement: it would be much better for agriculture to become a British responsibility.

According to Laura Kuenssberg of the BBC: “She will reinforce the possibility that as powers come back from Brussels, whether over fishing, farming or anything else, they could go to the devolved administrations ... but she’s not at a stage of making promises on specifics.”

No doubt Nicola Sturgeon had something to say to May about that.

Right through the fractiousness of the last third of a century, the practical result of any stand by Unionists on such petty principles has been to ensure that the Union did in practice become looser and weaker, with the result of an ever greater determination among Scots to seek political solutions inside a system of their own, at least in devolution or in independence as an ultimate goal. Theresa May is merely repeating the mistakes of Margaret Thatcher and Tony Blair.

If, then, in May’s aspiration, “as Britain leaves the European Union, and we forge a new role for ourselves in the world, the strength and stability of our Union will become even more important,”

the prospects do not look awfully bright. A woman so impervious to outside influences will no doubt have failed to note yesterday how the city where she came face to face with the First Minister of Scotland was one where the people showed on September 18, 2014, that they had in a majority cast off their allegiance to the UK. I wonder what plans May has, beyond exhortation, to win back the 54 per cent of Glaswegian voters who said Yes to Scottish independence? Nor are the 1.6 million other Scots who voted Yes likely to prove a softer target.

The façade of British unity looks even more cracked and crumbling if we cast our gaze across the sea to Northern Ireland, the other constituent of the UK to have voted for remaining in the EU.

It is noticeable that May’s vaunted last-minute tour of the UK’s lesser nations did not take her to Belfast, which admittedly has at the moment no government for her to consult with. Even if it did have one, or soon got one, it would be unlikely to add its piping notes to May’s whistles in the dark. For the province, the EU is a guarantor of its precarious peace, less in any formal sense than as a force for keeping the border open, and so, while doing no material harm to the Unionists (quite the contrary), soothing those nationalists always appalled by the partition of the island. There is in Ulster no majority for May’s unity either.

When the Prime Minister gets back to No 10 Downing Street and sits down to sign her letter to Brussels, she might reflect why it is that two outlying parts of the UK are still so impervious to her efforts to whip up some patriotic inspiration, so incapable of thrilling to the concept of a more united nation, a British nation that is.

She might recall that over several decades of national decline, a number of her predecessors in the highest political office have set their minds to the same problem and tried to define what Britishness is, to tell us what, among our obvious divisions, ought to be uniting us. It has to be said that none of them have come up with anything convincing. Britain may be no more than a collection of outdated political structures, practically incapable of reform, which actually stop the British people or peoples from aspiring to greater things. After Brexit, the English may come to feel this too.