Chief Treasury Secretary Danny Alexander has challenged SNP chiefs over what he branded as “fantastical” claims on future North Sea revenues.
The Inverness MP wrote to First Minister Alex Salmond in the wake of the latest cut in the forecasts for offshore receipts by the Office for Budget Responsibility (OBR).
But the SNP leader responded by suggesting that the Treasury was starting to suffer from “anxiety attacks” as the independence referendum draws closer.
The OBR downgraded its projections for the sector this week by £20billion over the period to 2041, triggering a renewed war of words over Scotland’s future.
In his letter, Mr Alexander said: “Nicola Sturgeon has said that you and your colleagues will ensure Scotland is ‘the most prepared nation in the world gaining new powers’.
“But with voting on the referendum just weeks away, you are still making plans based on untold oil wealth beyond anything independent forecasters consider plausible.
“This stage in the referendum campaign should be about presenting the people of Scotland with the facts about what separation would mean. Instead, you persist in offering a fantastical picture of a separate Scotland’s public finances.”
The Liberal Democrat said that SNP estimates for 2012/13 and 2013/14 were more than £5billion too high compared with what actually happened, and its predictions for revenues in the first three years of an independent Scotland was more than £12billion higher than the OBR forecasts.
Speaking on a visit to Aberdeen, Mr Salmond said: “If you put forward the positive case for the potential of this country, marry the huge natural resources of the country to the talented people, then we win the campaign.
“We win it because a positive argument about the future will always beat the negative scaremongering by the likes of Danny Alexander.
“I reckon down there in the Treasury when they see that 47% figure for the Yes vote already, the are starting to have anxiety attacks about what the next two months will bring”.
Read the full letter here: letter