Alex Salmond has challenged Nicola Sturgeon to reveal how she will "bend Westminster to the will of the Scottish Parliament" and persuade Boris Johnson to allow another independence referendum.
The former First Minister spoke out as the SNP leader prepared to launch the first of a new series of papers designed to form an updated prospectus for independence.
But the Alba Party leader said that without detail of how the UK Government could be made to change its mind and give the green light to another referendum, any debate about Scotland's future would take place in a "constitutional vacuum".
