The move follows the decision by Barclays Chairman Marcus Agius to quit yesterday, although he would stay in office until a succession plan is in place.
Both the executives had come under intense pressure to quit after the British bank was slapped with 290 million pound (USD 451 million) fine by the US and the UK authorities to settle the charges of manipulating global benchmark lending rates.
Diamond, who has served as the company for 16 years, resigns as CEO and a Director of Barclays with immediate effect, Barclays said in a statement.
"...The external pressure placed on Barclays has reached a level that risks damaging the franchise
