The chairman of Barclays Bank was tonight reported to be on the brink of stepping down as the row intensified over the Libor rate-fixing scandal.
Reports said Marcus Agius was about to leave the embattled bank, which declined to comment on the suggestions.
The development came as Business Secretary Vince Cable backed calls for a criminal investigation into bankers involved in the affair.
The Liberal Democrat Cabinet minister said the public could not understand why the perpetrators of "what looks like a conspiracy" were allowed to "just walk away".
The potential for prosecutions arising from the scandal has been downplayed by Treasury sources who point out that there are no criminal sanctions in place for manipulating the inter-bank lending rate, or Libor.
Libor is set on a daily basis by panels of banks and used to help set "swap rates" - the borrowing rate between financial institutions.
These rates in turn are used to price a vast range of products such as corporate loans and fixed-deal mortgages.
The rate-fixing scandal has engulfed Barclays
Lord Blair, a former head of Scotland Yard, added his weight to the call for a criminal investigation.
He said today that there had to be police inquiries into revelations that traders at Barclays, Royal Bank of Scotland (RBS) and other banks had tried to fix the rate.
"Anybody, the youngest detective, would say this is conspiracy to defraud. It can mean nothing else. And therefore someone has to launch a criminal inquiry into this behaviour," he told Sky News.
Mr Cable said the Serious Fraud Office was having "a fresh look" at the Financial Services Authority's investigation into the affair and that the public expected criminal prosecutions.
"They just can't understand why people are thrown into jail for petty theft and these guys just walk away having perpetrated what looks like conspiracy," he said.
His intervention came as it emerged that taxpayer-backed RBS has sacked four staff over their alleged role in the Libor-fixing scandal. The bank declined to comment on the matter but sources said the sackings were made at the end of last year.
It is understood they were traders Paul White and Neil Danziger, investment adviser Andrew Hamilton and Tan Chi Min, who used to work for RBS in Singapore.
As well as supporting the idea of a criminal inquiry, Mr Cable urged shareholders to stand up to executives and boards who had allowed "systemic abuse" to set in.
"Regulators are a backstop: they don't own banks," he wrote in an article for The Observer.
"The governance at the top of our leading banks has been shown to be lamentably weak. No one at the top of Barclays will take responsibility for systemic abuse.
"Shareholders, the owners, have a major responsibility here. I am bringing in legislation to strengthen their control over pay and bonuses, through binding votes, but shareholders have to get a stronger grip on weak boards and out-of-control executives."
His comments intensified the pressure on Barclays chief executive Bob Diamond, who is to be hauled before MPs on the Treasury Select Committee on Wednesday to answer questions about the scandal which landed his bank with a £290 million fine last week.
Mr Agius will also be questioned by MPs, and is reportedly facing shareholder moves to replace him.
Lord Turner, chairman of the FSA, said while he believed steps had been taken to ensure rate fixing could not happen again, it was not covered by criminal law.
An independent review into the future operation of the Libor rate and the sanctions available for manipulating it is to be set up by the Government this week.
Treasury sources said the review, to be headed by an as-yet-undisclosed independent figure, would ensure a speedy response to the issue, resulting in amendments to the Financial Services Bill this summer.
Ministers are considering setting up a separate review into the professional standards of bankers.
But Labour leader Ed Miliband insisted the public would settle for nothing less than a full public inquiry along the lines of Lord Justice Leveson's into media standards.
He said those involved in the scandal should also feel "the full force of the law".
"Most working in financial services do a good job but quite clearly responsibility for these abuses goes beyond just a few rogue traders," he wrote in The Sunday Mirror.
"That is why Labour is calling for an independent public inquiry into the institutional corruption at Britain's banks.
"We need to ensure that those who have broken the rules feel the full force of the law. If prison sentences are appropriate for people looting a few pounds worth of goods from shops, they should also apply to bankers found to have plundered millions."
Prime Minister David Cameron said yesterday that the Government would ensure "the criminal law can go wherever it needs to".
Asked about calls for a wide-ranging inquiry, he said: "Let's take our time, think this through carefully... That's what I'm determined to do, and that's what we will do."