If the UK leaves the EU in about six weeks time, as now seems likely, Scotland will leave the EU as well.
Which, as I understand it, means that an independent Scotland would then need to reapply for EU membership and, until accepted, would need to survive on its own without hand-outs from London and from Brussels for anything up to ten years or so while Brussels makes up its mind about Turkey, The Balkan States, etc, before they get round to accepting Scotland's request to join.
And add on the costs if the Rest of UK insist on a Divorce Settlerment a la Brexit but for 300 years of marriage and not 50 years of marriage.
And then how much of the UK's £ 1.3 trillion debt transfers from London to Edinburgh after 300 years ?? Got to be some of it.....
It's going to be difficult for the heart to beat the head in a cost benefit analysis, I think, but never underestimate the size of the chip on someone's shoulder