"I would have thought Mackay would be frustrated enough with the absurd constraints he has to live with now. But to use sterling would make his life nigh on impossible. Why then does he want to go down that route? I wish I knew. Economically it makes no sense. The political economy of it is disastrous. It would tear the SNP apart after independence. And it would guarantee a crisis-strewn start for the new nation as it failed to deliver on any promise and all its potential.If Scotland wants to be free it has to have its own currency. Nothing less will do." - Professor Richard Murphy.