UK opposes Scottish exit amid bank run fears

British sentiment toward Scottish independence has hardened just days ahead of the referendum, a new poll shows, amid fears of a run on banks north of the border in the wake of "yes" vote.

Some 63 percent of people surveyed by market research firm TNS in England and Wales were against the idea of a Scottish exit from the U.K., up 2 percentage points from June.

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Opposition to independence was strongest among the over-65s, the poll found, with 75 percent against.

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Meanwhile, Swiss lender UBS said bank depositors would pull money from banks domiciled in Scotland with almost immediate effect of a "yes" vote for independence, potentially putting huge pressure on Scotland's banks.

Throughout the 20th century, every monetary union break-up "without exception" has been preceded by a "sudden deposit transfer" from one part of a union to another, global economist at UBS investment bank Paul Donovan said.

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"In the wake of a yes vote, we think there will be a deposit transfer from Scotland to England," he said, speaking at a media briefing in London.

"I think there would be almost immediate concern, a scramble on the part of bank depositors to find out whether their sort code is Scottish or British and people would be looking to have their money domiciled in Britain," Donovan said,

Pointing to the dissolution of the Czech and Slovak currency union, Donovan said deposit transfers in the case of monetary union break-ups always happen "faster than politicians can react."

Financial sector jobs would also likely migrate south, he said as "jobs will go where deposits go".

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The latest figures from TNS showed two in every five polled said the UK would be worse off without Scotland, but only 55 percent said they cared about the outcome of the vote, while 47 percent said Scottish independence would have no impact on their lives at all. The survey of 1,124 adults was carried out online.

"There is clearly greater concern about the prospects of a smaller U.K. than there was a year ago, but with around a half not caring about the result and thinking that Scotland's independence would not affect them, it seems that a great number of non-Scots are simply prepared to let matters take their course," Tom Costley, head of TNS Scotland said.

By CNBC's Jenny Cosgrave: Follow her on Twitter @jenny_cosgrave