Ed Miliband has called on the Barclays chief, Bob Diamond, to quit after the interest rate rigging scandal, and says he intends to force a vote to secure an independent investigation into banking similar to the Leveson inquiry.
Speaking on the day that Marcus Agius quit as chairman of Barclays, the Labour leader called on Diamond to follow suit as part of a general change of leadership at the top of the organisation.
Admitting that the last Labour government made mistakes over bank regulation, Miliband called for an overhaul of the industry and for a code of conduct to be established for bankers.
Agius quit on Monday, saying he was "truly sorry" for the interest rate rigging scandal which had dealt a "devastating blow" to the bank's reputation.
Despite mounting calls for his departure, Diamond, who presided over the division where the rigging took place, showed no signs of leaving as he pledged to fully implement the findings of an independently led audit into bank practices since the financial crisis.
Miliband told ITV Daybreak that Diamond had called him to "try and give his side of the story", but he stood firm on the need for him to go.
"If you go out and nick £50 from Tesco, you are punished, at least we hope that you are punished – if you fiddle, lie, cheat to the tune of millions of pounds, you should also have the full force of the law brought against you.
"I don't think that he can carry Barclays forward, Bob Diamond, because he was there, he was actually in charge of the part of Barclays where some of these scandals took place years back and we will obviously hear what he has to say at the [Treasury] select committee on Wednesday but I really don't believe that the leadership and restoring trust in Britain's banking can be done by Bob Diamond."
He made clear that quitting alone was not enough because that would not get to the bottom of "what happened, who is responsible and punishing those who did wrong".
"I want to see criminal sanctions against those who broke the law," he said.
And instead of more "sticking plaster solutions", an independent inquiry similar to the Leveson one into media standards, was needed.
Miliband conceded that Labour "got it wrong" on bank regulation while in office, but he underlined his intention to learn from those mistakes.
"I think the lack of regulation was wrong, I think it was definitely wrong and it has got to change for the future. The bankers are going to be saying: 'Don't over-regulate', and of course we have to be careful, but I think we have had enough now of sticking plaster solutions.
"The scandals of the press have led to the Leveson inquiry. Now, some people in the press don't like that but at least everybody's coming forward talking about what they are doing. And we are going to put down an amendment in parliament in the coming days – I hope to try and put forward to the government to have that inquiry [into banking]."
He added: "I do say to David Cameron that getting everything out in the open is the best way forward and people are beginning to wonder: 'Has he got something to hide?'"
Labour is due to table an amendment on Monday to the financial services bill – currently at committee stage in the Lords – which it hopes will be debated "at the earliest opportunity", according to a party source.
Diamond, who was in charge of Barclays Capital when the breaches took place, said Agius's decision "deserves all of our respect".
"I welcome the board's undertaking of an independent, third-party audit of our business practices.
"I am committed to ensuring that the recommendations from this review are implemented in full, as part of a broader programme to continue to build a culture that all of those with a stake in Barclays can be proud of."
But John Mann, a Labour member of the Treasury select committee, said Diamond was ultimately the one who should accept responsibility.
He echoed Miliband's call for the American banker to resign, saying there was no role for him if the sector was to regain its reputation.
He told Sky News: "I'm sure that Diamond will want to pay back the bonuses that he wrongly got on the back of lies, and in essence defrauding homeowners across Britain, because that's what happened. But then he must resign – he's got to go."
Lady Patience Wheatcroft, a former Barclays director, told Sky News that Agius was "carrying the can" and it was inevitable that Diamond would step down.
Agius is still expected to face the select committee on Thursday – irrespective of his decision to quit.
