Barclays boss Bob Diamond is facing mounting calls to quit as he said all those responsible for the rate-rigging scandal should pay the price.
With Britain's biggest banks facing the threat of a criminal investigation over the activity that could cost the industry billions of pounds, the under-fire chief executive has agreed to a grilling by MPs.
Prime Minister David Cameron said it was very important that accountability for what went on "goes all the way to the top of that organisation" and that Mr Diamond had "some serious questions to answer".
In a further blow, the Financial Times called directly on the senior banker, who it said was behind the bank's "hard-driving culture", to step down. "If he had an ounce of shame he would immediately step down," the newspaper said in an front page editorial.
The sector was also braced for its public image to take a further battering with the Financial Services Authority (FSA) due to reveal it has found evidence that banks are embroiled in another scandal.
A review into the way lenders pushed so-called interest rate swap arrangements (Irsas), which have landed small businesses with spiralling bills, is expected to have uncovered mis-selling.
Barclays shares slid 15% on Thursday - wiping £3 billion from its market value - as investors ditched the stock amid fears £290 million fines could be dwarfed by lawsuits and damages. It was hit with the penalties by UK and US regulators for fixing the interbank lending figures that affect millions of homeowners and small firms.
The controversy, which covers a period between 2005 and 2009, could spread to other lenders, as RBS, HSBC, UBS and Citigroup are also being investigated. Serious Fraud Office investigators are in talks with the FSA over the scandal.
Chancellor George Osborne told MPs the rate-rigging scandal was "a shocking indictment of the culture of banks like Barclays in the run-up to the financial crisis".
Mr Diamond, who was in charge of Barclays Capital at the time the breaches occurred, has apologised and, along with three other key executives, waived their bonuses for this year. On Thursday night, he accepted a summons from the Commons Treasury Select Committee to appear before the influential cross-party panel to answer for the bank's behaviour.