In his optimistic (and very well worth reading) article about what Scottish independence could mean, John Fund writes:

Scotland would probably keep using the pound as its currency, which it could do with or without Britain’s permission, much as Panama and Ecuador use the U.S. dollar today. The stringent policies of the Bank of England and the loss of subsidies could push Scotland to become more fiscally responsible.

That’s nice in theory, but if Scotland wants to join the EU (and it does), a step, incidentally, that would very substantially dilute its freshly won independence, it will — like all other new EU members — have to agree to accept the EU’s single currency as soon (more or less) as its economy satisfies the objective criteria that would qualify it for admission to the euro zone. If Scotland’s economy is a wreck, of course, it won’t have to worry about meeting those tests, but that is probably not the way that SNP leader Salmond wants to reassure potential voters worried about being forced to adopt a vampire currency that will make a mockery of their democracy, their economy and their newly won independence.

And, in the interim, the “Panama option” may not work either.

Here’s Szu Ping Chan, writing in the Daily Telegraph:

Scotland must choose between independence and keeping the pound if it wants to be part of the European Union, one of the bloc’s top officials has warned.
In a blow to the Yes campaign, Olli Rehn, vice president of the European Parliament and former commissioner for economic and monetary affairs, said keeping the pound without consent from Westminster “would simply not be possible” because EU membership requires countries to have access to an independent central bank.
All three main political parties in Westminster have already slammed the door shut on a currency union between an independent Scotland and the rest of the UK. . . . Responding to a letter to Danny Alexander, the chief secretary to the Treasury, Mr Rehn said “sterlingisation” – or using the pound without a currency union – is prohibited under European Treaty law.
“As to the question whether ’sterlingisation’ were compatible with EU membership, the answer is that this would simply not be possible since that would obviously imply a situation where the candidate country concerned would not have a monetary authority of its own and thus no necessary instruments of the EMU,” he wrote.

If the Scottish nationalists were serious about independence rather than power, its perks and privileges, they would be pushing for the excellent idea of a fully federal U.K. (with an explicit right of secession for each of its component nations) outside the EU.

That they are not says everything.