The National:

THIS will probably surprise you, but strictly in terms of international law, Boris Johnson is right – there is no "border" between Scotland and England. Neither, for that matter, is there one between England and Wales.

Only the UK’s "border" – the thing you have to cross to enter Great Britain and Northern Ireland – is officially recognised as a "border" by the rest of the world. People in many countries know there is a difference between Scotland and England and that there is a border between them, but governments prefer to deal with states and their borders, and sadly for Scotland that means the UK defines the border and it’s not the one between the Tweed and the Solway.  

By "border" the Prime Minister no doubt means the line on the map which distinguishes one sovereign entity from another, and as the UK Government’s Advocate General Lord Richard Keen reminded us in the Supreme Court last year, sovereignty resides with the UK Parliament – and you can argue with moral correctness that the Scottish people are sovereign, but Westminster and the courts say otherwise for the meantime.

In short, the Border as we know it is an irrelevance in international law at the moment, but the problem for the Prime Minister is that of course there is a border between England and Scotland. It’s just that as a Unionist he only sees the "border" as being the geographic boundary of the United Kingdom.         

It comes back to the four countries, one state situation. It surprises many people to learn that the current incarnation of the UK – the United Kingdom of Great Britain and Northern Ireland – is less than 100 years old. The name was only formally adopted in 1927, five years after the 26 counties that became the Republic of Ireland seceded from the Union.

Most Unionists talk about "the country" of the UK. In fact it is a unitary state made up of four countries, and the border between Scotland and England is very real and has been for centuries.

Or else why did the Scots and English fight each other over the "border" from time immemorial? Hadrian’s Wall was for centuries seen as the "border", by the Romans if not the people then residing in what became Scotland, but gradually the line between the Rivers Tweed and Solway was accepted as the boundary, though of course the country of England only dates from nearly a century after Scotland.    

The Border was not set in stone – literally, with border stones – until the Treaty of York in 1237 which ensured that Northumberland and Cumberland were part of King Henry II’s England, while Alexander II, King of Scots, was content to hold on to Berwick-upon-Tweed and what became the "Debateable Lands" north of Carlisle.

Berwick went to England in 1482 by right of conquest, but the Debateable Lands were only divided along Scots Dike in 1552, from when the Border has not changed.

So for 468 years there has been a clearly defined Border between England and Scotland. And Boris Johnson knows it – he just doesn’t want people to think of it in case we decide to make it a real internationally-accepted border by voting for independence.      

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