Scottish First Minister Alex Salmond on Tuesday warned Britain's finance minister over his threat to exclude an independent Scotland from the sterling zone, saying that self-rule would help reduce inequality across the UK.
The Scottish National Party leader called George Osborne's warning a "monumental error" at a lecture hosted by the New Statesman magazine in London.
"In the last three weeks people in Scotland have seen an array of approaches from the UK government -- what they apparently call their Dambusters strategy," he said.
"We were love-bombed from a distance by (Prime Minister) David Cameron, then dive-bombed at close range by George Osborne.
"I believe George Osborne's speech on sterling three weeks ago, his sermon on the pound, will come to be seen as a monumental error."
Scots go to the polls on September 18 to decide whether to end their 300-year union with the rest of Britain.
A YouGov poll published on Saturday found 53 percent of Scots want to stay part of the United Kingdom, compared to 35 percent who think it should be an independent country.
Salmond argued that an independent Scotland would become an economic powerhouse, drawing deprived areas of northern England into its sphere of influence and diluting London's primacy.
"There's a growing realisation that wealth and opportunities are too concentrated, geographically and socially," he said.
"After Scottish independence, the growth of a strong economic power in the north of these islands would benefit everyone -- our closest neighbours in the north of England more than anyone.
"There would be a 'Northern Light' to redress the influence of the 'dark star' -- rebalancing the economic centre of gravity of these islands," he added.