A formal currency union would not be in the interests of an independent Scotland, the leader of the campaign to keep the United Kingdom together has said, stepping up pressure on nationalist plans to keep the pound.
With just over five weeks to go until the September 18 independence referendum, uncertainty over what currency would be used if Scotland leaves the United Kingdom remains a major campaign issue.
Britain's three main political parties have ruled out a formal currency union, but Scottish nationalist leader Alex Salmond has said that Scotland "cannot be stopped from keeping the pound".
However, Alistair Darling, a former Labour finance minister who heads the Better Together campaign, again ruled out a formal union. "It's quite clear that there's not going to be a currency union. It's not in Scotland's interest, it's not in the interests of the rest of the UK, so with five weeks to go we need to know what plan B is," Darling said.
Darling is seeking to capitalise on his strong performance in a televised debate last week, which was largely dominated by the currency issue.
A survey by pollsters Survation published on Saturday in the Scottish Daily Mail said 50 per cent planned to vote against independence, 37 per cent supported a split and 13 per cent were undecided.
The chief executive of Survation, Damian Lowe, said the 'Yes' campaign needed a "seismic change" to win, and had to answer key questions, particularly over which currency an independent Scotland would use.
But in an open letter published in The Scottish Sun on Saturday, Salmond said there was "absolutely nothing" that could be done to stop Scotland from using the pound and there was no alternative plan. "Plan B implies settling for what's second best. And neither myself, my colleagues in the [Scottish National Party] or the wider Yes campaign will ever settle for second best for Scotland," he said.