The CEO of British banking giant Barclays, Bob Diamond, resigned with immediate effect, the company reported in a shock announcement on Tuesday. He is the highest-profile victim so far in a probe over an interest rate-rigging scandal spanning major banks across the globe.

Despite earlier calls for Diamond to step down, banking experts had thought he would ride out the storm following the resignation on Monday of Barclays Chairman Marcus Agius. But the pressure simply became too big to handle.

"The external pressure placed on Barclays has reached a level that risks damaging the franchise, and I cannot let that happen," Diamond said in a statement.

Just hours after Diamond left, Chief Operating Officer Jerry del Missier, also announced his resignation. He was only appointed last month.

Investigations continue

US-national Diamond was in charge of Barclays' investment arm, Barclays Capital, at the time of the suspected interest rate manipulation.

The bank is now facing possible criminal prosecution in a scandal that has gravely tainted London's image as a financial center. Britain's Serious Fraud Office on Monday announced it was considering whether it was appropriate to initiate criminal prosecution, adding that it would reach a decision within a month.

British Prime Minister David Cameron had also announced a parliamentary inquiry into the revelations that Barclays traders had lied about the interest rate other banks were charging it for loans, known as the London Interbank Offered Rate (Libor).

hg,ng/pfd (Reuters, AFP)