Chief Executive Officer Robert Diamond has resigned from his post U. K's second-largest lender, Barclays Plc after the authorities announced an investigation into the interest rigging scandal involving the firma ns several others.

Barclays has lost three top executives, $5 billion of market value and is facing a government inquiry in the case. The bank is now facing a fine of a record 290 million pounds in the case. Diamond, 60, is likely to face questions from lawmakers at a Treasury Select Committee hearing on why the bank faield to stop the abuse of the interest rate system.

"The external pressure placed on Barclays has reached a level that risks damaging the franchise - I cannot let that happen," Diamond said in a statement. His resignation comes into effect immediately. Chairman Marcus Agius now has the responsibility to find a new CEO for the banking firm.

Diamond had written a strong letter to staff members indicating he will continue. However, he decided to quit after Prime Minister David Cameron and finance minister George Osborne announced an inquiry into the scandal.

Diamond had appeared before the parliamentary inquiry into the manipulation of interbank lending rates that underpins as much as $360 trillion of loans and financial contracts. Investigators have found that Barclays' traders rigged the Libor interest rate from 2005 to 2009 at a time when Diamond headed the British bank's investment banking operations.