This is an interesting issue. I’m not the right person to debate the merits of Richard’s argument based on (I think) MMT. https://twitter.com/richardjmurphy/status/1297823754005946368

We agree that it’s all in the end a matter of what is agreed between Scotland and rUK. The legal point is that there *has* to be an agreement if Scotland is to become independent by legal means: as the SG accepted, that requires Westminster legislation (as happened for Ireland).

The “game theory” point is that when (as would be the case here) two parties have to reach an agreement (neither can walk away) involving £* and there is no legal default rule (there isn’t here) there is no way of ascertaining what the £ outcome will be.

(*or, if you like,€)

In practice, though, I think the SG was right to assume that Scotland would have to take on a proportion of U.K. debt: that seems to me to be a hard political reality.

It isn’t just the Treasury that is sceptical of MMT. And whatever its merits, I just can’t see rUK politicians wearing a result in which Scotland is seen not to be taking on its fair share of a common debt.

There is, evidently, room for debate about what the right proportion would be: and I suspect that that debate would need to be settled in the agreement rather than kicked down the road to further negotiation with an arbitration in default (the Irish precedent).

But a proportion there would be, in my view.

Footnote: there is an oddity about the Irish precedent. Because in the end, the U.K. agreed not to pursue the matter. But that was a quid pro quo for the UK’s non-implementation of its obligation to review and adjust the Ireland/NI border.

Fortunately, though there would be many complexities in rUK/Scotland negotiations, the land border isn’t one of them (I hope - unless someone wants to re-open Berwick-on-Tweed - and, it being Twitter, I will probably soon find out that someone does want to do that.)

Second footnote: Richard is very kind, but there are academics on here who devote their lives to constitutional law and from whom I am constantly learning. So I can’t really let him describe me as an eminent constitutional lawyer: an engaged amateur in the field, more like.