In a letter to SNP ministers made public this weekend, the Chancellor points to figures from his Pre-Budget Report (PBR), which show that oil revenues will fall from 13.2bn this year to 8.7bn next year, as oil slumps to around $60 a barrel.
However, in a St Andrew's Day article in Scotland on Sunday today, First Minister Alex Salmond hits back claiming that it is the UK which is damaging Scotland, by cutting back on public services in the medium term.
The First Minister claims that the Treasury's plans to slash spending in 2010, as it attempts to reduce Britain's 1tn deficit, will lead to a cut of 500m in Scottish cash, the equivalent of Scotland's entire prisons budget.
The fierce row over the economy is set to dominate political debate in Scotland, with SNP ministers claiming last night that the cuts in spending will act as a boost to their campaign for independence. They hope to stage an independence referendum on St Andrew's Day in 2011.
But UK ministers are equally adamant that the global economic crisis provides ample evidence that Scotland's financial base would become highly unstable if it split from the rest of Britain.
In his letter, addressed to Finance Secretary John Swinney, Darling declares: "The Government's successful macro– economic policy enables the UK to manage the extreme volatility in North Sea revenue without disrupting public spending in Scotland next year as it would if there were fiscal autonomy in the form sought by the Scottish Executive.
"North Sea tax forecasts for next year are 4.5bn lower than this year, a fall of one-third."
Darling's figures are based on new projections for oil revenues calculated in the PBR. They show that oil revenues will rise from 7.8bn last year to 13.2bn this year, before falling back to 8.7bn in 2009-10. The fallback has been caused by the steep decline in the price of a barrel of oil from nearly $150 last summer to a predicted $60 throughout next year.
However, the SNP points out that, even with a fallback next year, oil revenues will come to 55bn over the next six years.
Salmond sets out the case today to claim that Scotland could follow the example of countries such as Finland and Norway as being among the few expected to continue to grow in the coming year.
He writes: "Control of all our own resources and the ability to borrow like any normal government would give us the chance to compete on a level playing field with the other countries currently able to use these tools to best suit them and see them through the global downturn.
"Unlike the UK, some small independent European nations like Finland and Norway are projected to keep on growing, with marginal growth in the Euro area as a whole, while the UK plunges into the economic mire."
Meanwhile, the St Andrew's Day battle is joined today by Scottish Conservative leader Annabel Goldie, who hits out at what she claims is the overtly political way in which the SNP Government is using the Saltire. She claimed that at recent by-elections the SNP had "wandered around shopping centres, stood at street corners handing out the Saltire as if they owned the flag, as if it was their exclusive property, as if they had a monopoly on the Saltire and it was their symbol".
She added: "As a proud and patriotic Scot I wish to make today the day when we reclaim the Saltire from the SNP and give it back to Scotland, all of Scotland."
Goldie continued: "It is time that the SNP grew up. Support for independence is not growing. It has remained more or less static for a decade or more. By a vast majority, Scotland does not want a broken Britain. We are happy to be Scottish and British."
However, Salmond writes today: "We believe Scotland should look after its own affairs not because we are intrinsically better than any other nation, but because we are as good as any other.
"We look forward with hope to the new year and to the one beyond, when we offer the people of Scotland the chance to choose the independent future that our nation needs to succeed."