FOREWARNED is forearmed: in the context of Brexit, and with the UK Government making a pig’s ear of the whole business, let’s take a look at another type of power grab it might try on Scotland. Scots law is one of the things that most distinguishes us from the English, and has done so ever since the Union of 1707. The treaty between the two nations says, at article 19, “That the Court of Session, or College of Justice, do, after the Union, and notwithstanding thereof, remain, in all time coming, within Scotland, as it is now constituted by the laws of that kingdom, and with the same authority and privileges, as before the Union.”

This sentence of the relevant article dealt with civil law, but it went on to specify that every other part of the Scottish system, the High Court dealing with criminal justice, the various specialist courts and then the whole structure of lower courts, in every burgh and in every county – as the treaty puts it, “all inferior courts, within the said limits, do remain subordinate, as they are now, to the supreme Courts of Justice within the same [Scottish system] in all time coming”.

These provisions were not meant to freeze the existing system. If that had been intended, Scots law surely would have ossified and crumbled to dust long before now. On the contrary, it had during the 17th century been developing from its feudal basis towards what the pioneering legal philosophers, Lord Stair and Sir George Mackenzie, regarded as natural law, law conforming to standards of civilisation that evolved as the human race rose out of a state of nature – all in contrast to the medieval jumble of English law.

Scots of 1707 expected their unique national evolution to continue. This was why they also provided for “such regulations for the better administration of justice, as shall be made by the Parliament of Great Britain”. I don’t think they expected this provision to be invoked often, or without care for the consequences. But they did not reckon with the presence at Westminster, even so early on in the Union, of malign Englishmen ready to twist the words of any mutual agreement to the detriment of the Scots, and ram home how Scotland was now a subject nation that could be bent to the will of its bigger neighbour. In 1711, in the Greenshields case, the House of Lords overruled a judgment of the Court of Session and in effect declared itself to be an appeal court for Scotland in civil cases. Clever Scots lawyers got revenge in their own way. They sent thousands of appeals to the Lords to be heard by English judges who had not the faintest idea about the law that lay behind them, as they loudly complained. It could not have happened to a nicer lot of chaps.

But at length the English tired of goading the Scots, and turned to oppressing the peoples of distant continents instead. Right down almost to our own day, two systems of law coexisted with little trouble inside the UK. But then a couple of things happened to ruffle this rapport. One was the Scotland Act 1998, which incorporated the European Convention on Human Rights directly into Scots law. The second was the establishment of the UK Supreme Court in 2009 to take over the former appeal functions of the House of Lords, which by now even the English had decided was unfit for purpose, and in particular to hear appeals under the ECHR.

This did not further alter the dual legal system in the UK, except in one aspect. Those clever Scots lawyers now had a motive to dig around in criminal cases for some connection to the ECHR, for some way in which the human rights of an accused might be held to have been breached. The purpose was to allow, on these grounds, an appeal to the UK Supreme Court, so that he had a further chance of getting off.

It began to change the way we had been used to doing things in Scotland. Peter Cadder, a teenager from Glasgow, was convicted of assault in 2009, after he had been questioned by the police without a lawyer being present. This had not worried the Scottish High Court, but the UK Supreme Court decided to quash the conviction. A second case was that of Nat Fraser from Nairn, convicted in 2003 of murdering his wife Arlene, though her body had never been found. The Supreme Court quashed his conviction too, on the grounds that, at his trial, evidence which might have affected the outcome had not been disclosed. For both these men, a breach in their human rights overrode the fact that they had been found guilty by the courts trying them.

Such cases pose us a question: have we been living through an era of further attacks on the independence of the Scottish judiciary, or has this rather been a beneficial process of bringing Scots law into line with European standards, if at the hands of judges sitting in London? But before we can work out a full answer to the question, it is being overtaken by Brexit. The UK’s references to the ECHR in internal legal matters are not directly affected because it does not form part of the EU treaties. But advocates of the hard Brexit now ascendant at Westminster take no kindlier a view of the one than of the other.

Here is what that angel of mercy and tolerance, Theresa May, had to say while still at the Home Office, which is always a good place to look for her basic instincts at work: “The case for remaining a signatory of the European Convention on Human Rights – which means Britain is subject to the jurisdiction of the European Court of Human Rights – is not clear … The ECHR can bind the hands of Parliament, adds nothing to our prosperity, makes us less secure by preventing the deportation of dangerous foreign nationals … If we want to reform human rights laws in this country, it isn’t the EU we should leave but the ECHR and the jurisdiction of its Court.” If that is Theresa May, what can we expect of Boris Johnson?

One idea afloat among these tyrannical Tories is that the UK should, instead of the ECHR, pass a new Human Rights Act of its own, so as to sever what after Brexit would otherwise be the most important of our remaining links with Europe. This Act would completely repatriate all human rights and would need to provide, within the borders of the UK, for a court of final appeal on them. That, surely, has to be the Supreme Court sitting in London.

It would also mean amending the Scotland Act 1998 to make this conform with the new arrangement. Then those Scottish criminal cases with some element relating to the human rights of the accused, which before 1998 would have been decided in Scotland, would “in all time coming” be decided by a court based in London and containing a majority (ten out of twelve) of English judges – not as part of some European arrangement but because the Union would have been recalibrated to make it more centralist. As a result a small but significant slice of Scottish jurisdiction would be shaved off for good.

We can see power grabs are on the agenda of May’s ministers from their shifty, evasive answers when asked if all the responsibilities that used to be with the old Scottish Office but were transferred to Brussels while we remained in the EU – agriculture, fisheries, environment – will be returned intact to Edinburgh after Brexit.

The answer is: not necessarily, the UK government may hand some powers back or keep some for itself, just as it chooses, in any case by diktat, not by agreement with the government of Scotland.

There is the same danger to Scots law from the advocates of a hard Brexit. If we can somehow manage a soft Brexit, that will increase the chance of keeping ECHR. If not, then I would say we require a new Human Rights Act of our own for Scotland – one which, for example, takes a more generous view of migrant workers and of refugees than any English Act is likely to do. It should be wholly under the jurisdiction of Scots judges and so bolster the independence of the Scottish legal system, something that needs the continuing vigilance of everybody lucky enough to live under it.