Sterling dived to its lowest in nearly 10 months against the dollar today after an opinion poll for the first time showed Scotland was ready to vote to break up its three-century-old union with the rest of the UK.
With just 10 days to go before the referendum, a YouGov survey for the Sunday Times newspaper put the "Yes" to independence campaign at 51% against the "no" camp at 49%.
Until a week ago, the risk of the Scots departing had been regarded by financial markets and London-based authorities as unlikely.
Leaders of Britain's main political parties were scrambling to respond by promising a range of new powers for Scotland if it chooses to stay within the United Kingdom.
Sterling sank more than 1% - its most in 13 months - to trade at $1.6145 against the dollar in early European deals. It was also almost 1% lower against the euro.
The UK economy has outstripped all of its major peers in Europe over the past 18 months, driving the currency as much as 15% higher against the dollar and, while growth is set to slow somewhat, the Scottish vote is not expected to upset that picture.
Analysts warn that there are substantial risks to business and financial markets in the potentially fevered negotiations that would follow a "Yes" vote, but after a week of selling it is possible that the bulk of the initial risk to sterling is priced in.
