Barclays Plc Chairman Marcus Agius quit on Monday and said an interest rate rigging scandal had dealt "a devastating blow" to the bank's reputation and "the buck stops with me".
Agius, chairman at Barclays for 5-1/2 years, will stay in his position until a succession plan is assured.
Pressure has built on him and CEO Bob Diamond to quit following a $453 million fine for Barclays by British and U.S. regulators last week for submitting inaccurate submissions on the Libor interest rate.
"Last week's events - evidencing as they do unacceptable standards of behaviour within the bank - have dealt a devastating blow to Barclays reputation ... the buck stops with me and I must acknowledge responsibility by standing aside," he said in a statement.