Ratings agency Moody"s has downgraded the Co-operative Bank"s debt rating to "junk" status, citing fears that it is vulnerable to potential losses report Northampton charterd accountants Harris & Co.
The agency warned that the bank may need "external support" if it could not strengthen its balance sheet.
The Co-op said it was "disappointed" by Moody"s decision.
The news preceded the resignation of chief executive, Barry Tootell, following the bank"s failure to buy 630 branches from Lloyds Banking Group