The pound has fallen to its lowest level in 10 months amid uncertainty about Scotland’s future within the UK.
The currency fell 1% against the dollar in early trading to $1.6159, and also fell almost 1% against the euro to 1.2480 euros.
It came after a YouGov poll suggested supporters of an independent Scotland had taken a narrow lead in the referendum debate for the first time.
Just a week ago sterling was trading at $1.66 against the US dollar.
Shares in Scottish-based firms dominated the top fallers on the stock market. Edinburgh-based Standard Life fell 3%, Royal Bank of Scotland slipped 2.4% and Lloyds Banking Group, which owns Bank of Scotland and Scottish Widows, dropped 2.7%.