Marcus Agius has resigned from his role as chairman of the British Bankers' Association (BBA), the trade association said.
A statement from the BBA said: "Marcus Agius has tendered his resignation as chairman of the British Bankers' Association.
"This is a matter for the board and a meeting will be held shortly. A further statement will be made in due course."
Bob Diamond tonight angrily rejected suggestions that he misled MPs over regulators' concerns about activities at Barclays.
The Bank of England's Paul Tucker told MPs he refuted claims that he attempted to influence Barclays into manipulating the Libor rate.
MPs will be hoping the Deputy Governor of the Bank of England will shed some light on unanswered questions about rate-fixing at Barclays.