Shares in Barclays traded at a two-and-a-half-year low in early trading, amid speculation about rumoured liquidity problems at the bank.
The value of the lender's stock fell by as much as eight per cent before trading down six per cent at 10:45 GMT.
Reports suggest the fall in Barclays' share price has been prompted by rumours that the bank may have approached the Bank of England for emergency funding.
Both Barclays and the UK's central bank have declined to comment on the claims, although the latter's daily report on money market operations shows that no emergency loans were made to any of the nation's lenders at its penalty rate yesterday.
But some analysts have said it is unlikely that Barclays has sought cash under the Bank of England's emergency lending facility, while acknowledging that concerns do exist about the possibility of write downs at the bank due to the ongoing global credit crunch.
Unease is growing in the markets about the extent to which British banks are exposed to problems in the credit markets, with the ongoing global credit squeeze having been prompted by rising default levels in the US sub-prime mortgage market.
Speculation about the financial position of Barclays, which has always denied having funding difficulties, first occurred in August after the lender was twice forced to borrow overnight funds from the Bank of England due to technical difficulties.
Meanwhile the extent to which stricken lender Northern Rock appears to be reliant on emergency cash from the central bank has been criticised.
Bank of England figures released yesterday appeared to suggest that the Newcastle-based lender has borrowed almost £23 billion from the institution to date.
It emerged that Northern Rock had first approached the Bank of England for an emergency loan in September, prompting the first run on a British bank in almost 150 years and leading the government to guarantee savings held with the lender in order to restore confidence in the banking system.
Commenting on the taxpayer's apparent level of exposure to Northern Rock's current difficulties a former member of the Bank of England's monetary policy committee said the central bank could not continue to prop up the lender.
Speaking on the Today programme Professor Willem Buiter said Northern Rock appeared to have borrowed an "extraordinary" amount of money.
Referring to the Bank of England's reported loans to the company he added: "It is becoming state aid, it's no longer just a rescue operation for a temporary emergency.
"This bank seems to be unable to fund itself on commercial terms even now that markets have settled to a large extent," Professor Buiter stressed.