Alex Salmond claims Danny Alexander has been "caught red-handed" with "scaremongering" claims about the impact of Scottish independence.
The SNP leader told the BBC the Treasury's calculations had been "blown to smithereens" by the same academic whose work underpins the British Government's analysis.
Professor Patrick Dunleavy of the London School of Economics said Treasury figures about the cost of setting up a new independent government were "bizarrely inaccurate".
Mr Salmond seized on Professor Dunleavy's words, saying: "We have the Chief Secretary to the Treasury left with no credibility whatsoever. He’s been caught red-handed engaged in a scaremongering campaign.”
More top news
The footage, taken from a dead Islamic State militant, shows the fighters in a chaotic and panicked battle with Peshmerga forces.
Solicitors acting for 20 of the families said they were "appalled to see the shambles in South Yorkshire Police" following the inquest.
The two men are accused of meeting with Mohamed Abrini and giving him money.