Bob Diamond has resigned as CEO of Barclays, the company said in a statement Tuesday.

Diamond, who will leave his role with immediate effect, has been under pressure for several days since regulators in the US and UK fined Barclays £290m ($450m) over allegations of attempts to rig a key interest rate known as the London Interbank Offered Rate, or Libor.

His departure follows the resignation Monday of Barclays Chairman Marcus Agius, who indicated he will remain in his role until the search for his successor is complete.

However, his position has now been reconsided and the company says he will now return to his role as full-time Chairman and lead the serach for a new CEO.

Chancellor George Osborne, who was told of the resignation by Agius late Monday, told the BBC's "Today" programme that Diamond's resignation was "good for Barclays and good for the country and I hope it's a first step towards a new culture of responsibility in British banking."

Both Agius and Diamond, 60, are due to appear before lawmakers on the Treasury Select Committee on Wednesday and Thursday to answer questions regarding the growing controversy surrounding not only the Libor-fixing allegations, but also banking ethics and culture in general. Prime Minister David Cameron's coalition government has called for an inquiry into the future of Libor, a key benchmark lending rate across 10 different currencies that forms the pricing foundation for hundreds of trillions of dollars worth of securities worldwide.

Barclays shares have fallen 15 percent since the FSA announced its record fine on 27 June, wiping away more than £3.6bn in shareholder value. Diamond and three of his most senior colleagues, chief operating officer Jerry del Missier, corporate and investment banking head Rich Ricci and finance director Chris Lucas, have all waived their bonuses for this year as a result of the fine and accompanying explosive allegations.

Both the UK's Serious Fraud Office and the US Department of Justice are either actively investigating the allegations of bid-rigging or considering launching a formal probe into the matter.

Barclays London