There are few who would argue that Union has been other than beneficial to Scotland. The 18th century saw a steady improvement in the Scottish economy and a flowering of philosophy, science and invention. The firm of Boulton and Watt, a hugely successful marriage of Scots invention and English money, might typify the period. In the 19th century Scotland began to punch far above its weight in the building of the British Empire.

The peripatetic Scots engineer moving around the Empire building docks, bridges and railways became a virtual stereotype. Many of his compatriots served as soldiers, garrison commanders, colonial administrators, educationalists, missionaries and businessmen.

Scotland has always punched well above its weight in the British Union, as well as the historical Empire.

To take but one example, the number of Scots and people of immediate Scottish extraction who represent English seats in the House of Commons has been, and continues to be, both considerable and reflective of the situation throughout the public, scientific, commercial, and academic community.

The interlock between Scots and English has not only been political and territorial. Recent DNA analysis shows that the English are much more Celtic/Gaelic than previously thought, whilst the Scots show surprisingly similar ingresses of Norman, Saxon and Norse. Unsurprisingly the north of Scotland owes much of its genetic origins to the Baltic shield, but then so does the east and north-east of England. Aside from the inevitable and numerous local variations, there is little to set the two peoples apart in terms of genetic heritage.

SUNDERING THE THICKNESS OF MUSCLE AND BONE
So to the present conundrum of Scottish independence.

There is a strict limit to the extent that adversarial brows can, on such an emotive subject, be soothed with a little history.

Yet that history serves to demonstrate the thickness of the muscle and bone that must be sundered for both countries to go their separate ways.

As with the separation of Siamese twins, a mass of veins, nerves, arteries and tissue will have to be painstakingly scalpelled asunder in an operation of great duration, complexity and hazard.

There is a general impression that little practical thought has actually been given to the complexities of severing two sub-nations which have been entirely joined as a single nation for three centuries, partially joined for four, and have a complex mutually interlocking social and political history going back perhaps a millennium or more.

As far as the separatists are concerned, few of the issues that follow have had more than the briefest of thumbnail sketches by way of thought or resolution.

We must think of all that has to be disaggregated.

Starting at the small details - and small details can often carry a symbolic and totemic baggage which will make them vexatious far beyond their fiduciary worth - all the national museum collections could create serious difficulties. Do items of historical and artistic value of Scottish origin but housed in English museums and galleries have to be returned to Scotland and visa versa?

The two countries would have to agree on the disaggregation of the railway network, air traffic control, the university admissions system, the meteorological office, the Competition Commission, the BBC, and a huge spate of other commissions, agencies and quangos.

Moving up a further rung we would be confronted by disaggregation of border controls, the passport office and most complex of all given that a large number of Scots might still be living in England and a large number of English in Scotland - the national insurance, tax and social security systems.

More difficult questions still lie beyond that.

Who gets the foreign embassies and in what proportion? That is, providing our embassies will not, by then, be subsumed into a European diplomatic service, in which case - as has already been remarked - the separation of England and Scotland will become pretty well pointless anyway.

Again subject to the European caveat, the disaggregation of the defence forces could prove fertile ground for dispute. Will any Scottish forces continue to be based in England and visa versa? How do we disaggregate the overseas bases in Cyprus, Germany, Gibraltar and the Seychelles? Who gets what assets? Will English warships continue to be built in Scotland?

Then what becomes of the residual British overseas Territories? Do we divide this responsibility proportionately and if so who gets what? On the other hand, do they stay under some form of joint control?

What of Scotland's long and deep relation with Northern Ireland? Is Northern Ireland to be attached to the residual English and Welsh parliament, to the Scottish or to a bit of both?

And what is to become of the permanent seat on the UN Security Council? Will that be English, Scottish, or a joint preserve? Or will it disappear entirely leaving both states far less than the sum of their parts?

Last, but by no means least, we come to the economic issues. How do we divvy up the national debt, more especially as it is now likely to burgeon massively - and in a way that might have ramifications for decades - in the wake of the economic crisis?

Would the English Treasury and the Bank of England retain any control over Scots banks, especially as these are now so dependent on a Whitehall bailout? Would the Scots tell the English that they can keep the debt and Scotland will start with a clean sheet, thank you very much? How could that be acceptable to England?

The issue of national debt could prove the most intractable of all. The issue of 'Scottish' oil versus the Barnett formula, with the historic balance of economic advantage that each side would respectively claim, even has all the potential to start a fighting war.

As for the oil, there are issues regarding ownership between not just England and Scotland but, since the Lisbon Treaty, also the European Union. Further, if the Anglo-Scottish border is extended north eastwards in a straight line, and there is every precedent in international law for so doing, the assertion that a good part of this oil is actually Scottish begins to unravel. There are also those in the Orkney and Shetland islands who might have other ideas about the ownership of this black gold.

If such acrimony were not enough, what of the several million Scots, and those of immediate Scottish descent who live in England, and those English and of immediate English descent who live in Scotland? If you have an English father and a Scottish mother, were born in Falkirk but live in Birmingham, are you English or Scottish? Many children of this divorce could thus be turned into orphans.

Divorce is rarely convivial and this one could get a good deal nastier than most. There are all the makings of an extremely protracted and acrimonious dog's breakfast.

It is hard to see how a vicious fracture in the social union between the two countries could be avoided.

Even if this were accomplished, none of us knows what the future might hold. In the fullness of time, one country might be in the Schengen area and the other out. One country may be in the Euro, and the other out. One country might even be in the European Union, and the other out - leaving aside any thought as to whether a separate Scotland would be acceptable to other European states, such as Spain and Italy, with secessionist worries of their own.

Even now the government is considering the introduction of passports for travel to the Irish Republic, Northern Ireland, the Isle of Man, and the Channel Islands.

Against such a background, the advent of a barbed wire frontier between Scotland and England must be rated a high probability, verging on a certainty, rather than a mere possibility.

We would see all the horrible panoply of customs and passport checks at Berwick and Carlisle and right along the border! It would be a new Hadrian's Wall in every sense. I leave the reader to consider what impact such an imposition might have on the Scottish economy and of the relative preference for investing in England - already a vastly larger market - than in Scotland.

I leave the reader to consider what effect that would have on any residual "social union" between the two countries, and what effect it would have on the orphans of this divorce and their families left on both sides of the border.