Barclays chief operating officer Jerry del Missier has followed chief executive Bob Diamond out of the door in the wake of the rate-rigging scandal.
Mr del Missier, who worked with Mr Diamond at the bank's investment arm Barclays Capital between 2005 and 2008, was only promoted to his current role last month, but has been with the bank for 15 years.
He said he had every confidence that the board would be "successful in executing their plans".
His resignation came shortly after Mr Diamond quit amid increasing pressure from politicians, shareholders, financial campaigners and former directors.
Barclays has been at the centre of a gathering storm over banking ethics after it was last week fined £290 million by UK and US regulators for attempting to fix the key interbank lending rate.
Mr Diamond, who also resigned with immediate effect, will reportedly be asked to give up nearly £20 million in unvested shares awarded to him in previous years.
Alison Carnwarth, chairman of the remuneration committee, will ask Mr Diamond, who was awarded a total of £17.7 million in 2011 alone, to hand back the bonuses, Sky News said.
The speculation comes after proxy-voting and corporate governance service firm Manifest estimated Mr Diamond had earned at least £120 million since joining Barclays' board in 2005.
Mr Diamond, 60, who was with Barclays for 16 years, is expected to "speak more freely" when he appears before MPs tomorrow now he is no longer at the helm.
He is expected to shed more light on conversations with the Bank of England which led staff to mistakenly believe they were instructed by the central bank to manipulate the Libor, the rate at which banks lend to each other.
Meanwhile, reports claimed Bank governor Sir Mervyn King and Financial Services Authority chairman Lord Adair Turner last night encouraged Mr Diamond's exit.
Mr del Missier took up his current position in June 2012 after spending three years as co-chief executive of corporate and investment banking.
In his most recent role, Mr del Missier was responsible for overseeing the construction of a ringfence around the bank's retail arm, separating it from the investment division, as proposed by the Independent Commission on Banking last year.
Chancellor George Osborne, who on Monday announced a parliamentary probe into banking standards, said Mr Diamond made the "right decision" for the bank and for the country.
While Labour leader Ed Miliband also backed the departure, he continued to call for a full judicial inquiry into banking culture and accused the Prime Minister of failing to recognise "the gravity and scale of this crisis".
Mr Diamond, who was once dubbed the "unacceptable face of banking" by Lord Mandelson, remained defiant in his resignation statement.
"I am deeply disappointed that the impression created by the events announced last week about what Barclays and its people stand for could not be further from the truth," he said.
He added: "My motivation has always been to do what I believed to be in the best interests of Barclays. No decision over that period was as hard as the one that I make now to stand down as chief executive.
"The external pressure placed on Barclays has reached a level that risks damaging the franchise - I cannot let that happen."
Chairman Marcus Agius, who resigned over the affair on Monday, will remain with the bank to lead the search for a new chief executive before stepping down at a later date.
Despite mounting calls for his departure, Mr Diamond's exit came as a shock as he had showed no signs of leaving his position after pledging to see an internal review through to the end.
IG Index market analyst Chris Beauchamp said Mr Diamond's appearance before MPs could contain "interesting revelations", while Hargreaves Lansdown Stockbrokers' head of equities Richard Hunter said it would throw light on "internal turmoil at the bank".
The FSA's report said there had been a misunderstanding arising from a conversation between Bank deputy governor Paul Tucker, a favourite for the governor role, and an unidentified senior Barclays manager on October 29 2008.
The Chancellor said a parliamentary review, led by Treasury Select Committee chairman Andrew Tyrie, will look at "transparency, conflicts of interest, culture and the professional standards" in the banking industry.
Speaking after Mr Diamond's resignation, Mr Osborne said: "I think he has clearly taken the view that Barclays has a better future without him than with him."
He added: "But I think it is the right decision for Barclays, I think it is the right decision for the country."
Earlier, Barclays said Mr Diamond's severance pay package is "still under discussion".
The bank's most recent remuneration report, for 2011, said executive directors are entitled to a notice period of 12 months and payment in lieu of notice in instalments.
This means Mr Diamond could be entitled to a full year's salary, which in 2011 was worth £1.4 million.
However, the report adds that the remuneration committee's approach when considering payments in the event of termination is to take account of the individual circumstances.
Some 32% of investors voted against or withheld votes for the bank's pay report at its annual meeting in April after the bank recorded a return of equity of just 5.8% in 2011, down from 7.2% in 2010 and far from Mr Diamond's target of 13%.
Speaking at the FSA's annual meeting, Lord Turner said: "The Libor scandal has caused a huge blow to the reputation of the banking industry."