This is a very interesting and well written piece by Alex Bell in Rattle. He had been the Head of Policy for Alex Salmond for 3 years and his criticism is thus very revealing. He is quite clear that, on the economic arguments the SNP offer at the moment, their model of independence is broken and will not work. He describes the problems in some detail and it is clear that the numbers do indeed not add up. It is very surprising that this has had relatively little attention as it deserves more. His last paragraph is worth reading even if you don’t open the article :-
SNP Independence has become the cocaine of the politically active, fun to join in but dulling the senses, jabbering on at a hundred words per minute while disconnected from self awareness. It is for another generation to do the hard work of thinking through all the implications, and then deciding if independence is the right thing to do. By that point Britain will be different, Europe will be different and the world will have fundamentally changed. Perhaps there is no harm in all of this: some political misdirection; ultimately settling for a better deal than before; nobody shot in the process. But it serves neither devolved Scotland nor the people who wish for independence.