North Sea oil revenue plunged to an all-time low in the first quarter of this year according to the Scottish Conservatives.
The Scottish government's quarterly national accounts show that it received £168m in tax receipts from the industry between January and March. This is down from £969m in the same period last year the Scotsman has reported.
A supply glut has sent brent, the global oil benchmark, down from a high of around $107 per barrel in June last year to about $45 per barrel today. Oil producers have had to make job cuts, as well as pull back from their more costly projects.
"The plunge in oil revenues for the first three months of this year is incredible. Whichever way you look at it, and with the best will in the world, there is just no way an independent Scotland could survive on this," Murdo Fraser, Scottish Conservative finance spokesman, said.
"We knew the price of oil was volatile, and that this would be a risk. But to see such a radical drop is alarming. Thankfully, within the strength of the UK, this shock can be absorbed."
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But deputy first minister John Swinney stressed that the Scottish economy is not solely reliant on the North Sea oil and gas sector.
"Oil, however, is a bonus, not the basis of Scotland’s economy. Even without it, Scotland’s output per head ranks third of the 12 countries and regions of the UK behind only London and the South-east," Swinney said.