EU mystery

I am yet again confused by issues raised about the independence debate criteria.

I cannot quite understand why it is so important to be a member of the European Union on the grounds that the EU is a principal trading partner with Scotland, yet is it is equally important to not be a member of the United Kingdom – which is a, if not the, principal trading partner with Scotland. Perhaps someone will do me the favour of an explanation.

David Gerrard Spylaw Park, Edinburgh