THE UK Government would impose stringent conditions if an independent Scotland kept the pound in a new "sterling zone," a former high-ranking Bank of England official has warned.

Brian Quinn, one of Scotland's most experienced bankers, said the move would "place many constraints" on an independent Scotland's economic and financial policy choices.

His warning came as Owen Kelly, head of Scottish Financial Enterprise, claimed the industry was crying out for clarity on what independence might mean in practice.

The pair's views, outlined in papers for a David Hume Institute seminar in Edinburgh tonight, deal a blow to First Minister Alex Salmond's idea of forging a sterling zone with the rest of the UK.

Mr Quinn, a former acting deputy governor of the Bank of England and now a director of Glasgow University Business School, said an independent Scotland's freedom to spend and borrow would be limited, as it would not be allowed to a run a significantly higher budget deficit than the rest of the UK.

He also said it was unclear whether Scottish banks would, as the SNP claim, continue to come under UK regulation, as the plan appears to be in breach of EU rules.

If a way to adopt the UK regime was found it would avoid the cost and time of establishing a Scottish regulatory framework, he said, but could place extra burdens on Scotland's banks if they were seen as operating in a riskier environment.

The move would also mean any decision to bail out a Scottish bank on the brink of collapse would be taken by the UK Chancellor.

Mr Quinn warned that under those circumstances it would be "a good deal more likely" that a struggling Scottish bank, whose collapse did not threaten the UK financial system, would be allowed to fail.

He also cast doubt on SNP claims that an independent Scottish Government would be represented on the Bank of England's key Monetary Policy Committee, saying the move would have little real effect and appeared "political than backed by any perceived economic rationale".

According to Mr Quinn, it was "not self- evident" that an independent Scotland would retain the UK's AAA credit rating, which allows cheaper borrowing. He also questioned Mr Salmond's pledge to save billions of pounds in an oil fund, given Scotland's higher levels of public spending.

"It seems most unlikely that the current UK Government and Parliament would fail to set conditions for Scotland's participation in a revised sterling zone," he said. "Electing to retain sterling as the currency for an independent Scotland would place many constraints on its freedom of action in virtually all of the other central areas of economic and financial policy."

Scottish Financial Enterprise chief Mr Kelly said: "There is a strong appetite for clarity about what independence would mean in practice and this runs strong in the financial services industry, where facts and evidence are always given preference over belief and sentiment."

Scottish Labour finance spokesman Ken Macintosh said: "When an expert such as Brian Quinn questions what independence would mean given the significant constraints Scotland continuing to use the pound would face, it is little wonder that Alex Salmond makes it up as he goes along."

A Scottish Government spokesman said: "An independent Scotland as part of a sterling zone will continue to support the cross-border flows of goods, services, and investment, benefiting both the Scottish and the rest of the UK's economies."