DW: Can you explain why the ECJ is such a bone of contention in the Brexit negotiations.

Sir David Edward: No I can't. To be honest I think it's partly due to confusion between the ECJ and the Court of Human Rights in Strasbourg. They're both referred to as the European court. And the court in Strasbourg has made a number of decisions adverse to the UK which some parliamentarians at any rate considered to be an intrusion on domestic autonomy. For example there is a case where more than once the court has held that the British policy of refusing a vote to all prisoners is contrary to the Convention on Human Rights. And that is thought to be an intrusion on British sovereignty. There have been cases where the ECJ has held that British immigration policy is incompatible with EU law, which offends that particular section of the Conservative Party and particularly Mrs. May, as she was home secretary [at the time]. Part of the origin is just the cry that we don't want to be ruled by foreign judges, entirely overlooking the fact that there is always a British judge in the court and the British have always had an advocate general in the ECJ.

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And I think particularly in England there is a belief that the English common law is superior to other any other system of law, and therefore to be told what to do by anybody else is not acceptable.

That's a pretty damning indictment if you say that members of Theresa May's cabinet don't actually understand the difference. Would that include the prime minister herself?

I think it does. For example the talk about ending the jurisdiction of the ECJ in the United Kingdom is misleading. The ECJ only has jurisdiction to decide cases that are properly brought before it. It's not to say that the ECJ has jurisdiction in the United Kingdom. It has jurisdiction to answer questions put to it by the judges of the United Kingdom and it also has jurisdiction in cases where the commission brings a case against the United Kingdom under the rules dealing with failure to fulfill EU obligations. But it doesn't have jurisdiction in the same sense as a Supreme Court or indeed any British court does.

If at the end of the process we have a so-called soft Brexit and the UK to a certain extent stays in the single market doesn't that entail that the UK would then have to adhere to ECJ decisions regarding single market laws?

Well, if you take the parallel situation of the EEA [European Economic Area - the ed.], Norway, Iceland and Liechtenstein are bound by the terms of the agreement and the agreement incorporates the free movement provisions of the EU treaties but the treaties don't apply directly in the EEA states. And so a soft Brexit wouldn't necessarily mean that the UK would be within the scope of the ECJ jurisdiction any more than Norway is. But if you're going to trade and the whole point of being in the single market is to have freedom of movement, then the ultimate authority on what the rules are within the EU 27 is the ECJ. So for example if there's a question over pharmaceutical standards and there's a dispute as to what the directive on particular pharmaceutical standards says, then the ultimate arbiter is the ECJ. And to that extent traders in the UK who want to trade with the EU 27 have to obey those standards. And the same thing applies in all aspects of freedom of movement.

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One of the main sticking points seems to be who has jurisdiction to resolve disputes over EU citizens' rights. Brexit minister David Davis recently said, well, we could set up an alternative arbitration body. What do you make of that?

Well, it is possible that there could be a new separate arbitration body but immensely complicated questions then arise. Who's going to be on this arbitration body? What resources is it going to have? Who are going to be the judges? How many cases is it going to have? I mean bearing in mind that the volume of cases going through the court of justice is enormous and you can't imagine that it would just be a panel sitting every three months or something. It might have to sit continuously depending on the volume of issues that arose particularly on the question of rights of EU citizens in Britain and likewise British citizens in the EU.

There are there are all sorts of practical questions. And let me give you an example about my own experience [on the court]. In my 14 years there I signed more than 1,300 judgments. I was rapporteur in more than 300 cases. That's an enormous volume of cases, and you can't assume that this is just going to be an occasional problem. And I just find all these assertions extremely facile because they don't really take account of the realities of the problem.

If both sides stick to their hard-line stance regarding citizens' rights it would seem we have an intractable problem on our hands. Is there likely to be a resolution?

Well put it this way: One very old EU hand said to me 'we will find a way, we always do.' And it is certainly true that it's always possible to find a solution to these problems. But we're talking about people's rights, individual rights and you have to go back to the very beginning of what the Court of Justice said about the treaties. The Court of Justice said that the treaties confer rights and obligations not only on the member states but also on their nationals. And part of the problem is that the British attitude seems to be that we're talking about an immigration problem. We're not talking about an immigration problem. We're talking about an issue of acquired rights, rights the people already have, and you can't just say oh well it's only people who've been here for five years that have these rights. As long as we are a member of the EU any person, any EU national who comes into the United Kingdom and settles here under the existing rules and brings his or her partner, or children or any other dependents then they have a right to be here now. It's nothing to do with whether they've been here for five years.

And that's what is simply not understood as far as I can see in the rhetoric that we get from the British government at the moment.

Finally, Sir David, can I get your prediction on the likely outcome of the Brexit talks?

 I think that depends very much on British politics. The prediction is that this prime minister will not last. Then the question is: Who's next; and depending on who it is the outcome could be very nasty. I mean a lot of people I have spoken to, particularly in Brussels, say 'I am now sure that Britain is going to crash out of the EU in March 2019 without any deal at all.' And that is perfectly possible if there isn't a greater understanding of what all this involves. Another part of what I hear is that there is now a serious possibility that because the problems have begin to appear more and more horrendous, and this great repeal bill throws up more and more ghastly questions of law, people are beginning seriously to say is all this worth it? And you have to remember that people have to consider the state of the British economy, and as the Chancellor of the Exchequer said some weeks ago, people didn't vote to become poorer. You know, [former prime minister ] Harold Wilson once said a week is a long time in politics. I think between here and March 29, 2019 is a geological era in politics.

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Professor Sir David Edward is Professor Emeritus at the School of Law, University of Edinburgh. From 1992-2004 he was a judge at the Court of Justice of the European Communities, later known as the European Court of Justice.