Scottish independence: Darling on Salmond referendum plan
26 November 2013 Last updated at 14:38 GMT
Those backing Scottish independence "have told us absolutely nothing new" said the leader of the campaign to keep the Union, as a 649-page white paper was launched.
Alistair Darling said a currency union would lead to a democratic issue with London and Edinburgh having "to agree each other's tax, spending and borrowing", and the nationalists had changed their currency position "three or four times in the last two years".
And he said there was "no Plan B if it does not work out, or the terms and conditions are not acceptable".
The Labour MP and former chancellor spoke to Jo Coburn after Alex Salmond launched the Scotland's Future: Your guide to an independent Scotland document. She later spoke to the SNP's John Swinney,