"The SNP hierarchy want Scotland to pursue ‘sterlingisation’ post independence. That would mean Scotland would use the existing pound. And this would be an outright disaster. Scotland could not, in that case, borrow in its own currency. It could not set its own interest rates. It could not do quantitative easing. It could not have done furlough then. And its debt would be subject wholly to the whim of foreign financial markets, and you can be sure that those in London would do their best to undermine it."
https://www.taxresearch.org.uk