Barclays chief executive officer Bob Diamond announced his resignation this week, saying he is stepping down because "the external pressure has reached a level that risks damaging the franchise."

He added, "I cannot let that happen."

Reuters reports that Diamond has been under the gun from politicians due to a scandal over the alleged rigging of interest rates.

Diamond opted to step down from his director position as well. Marcus Agius, who also is stepping down as chair, will continue to serve as chairman until new successors are found.

The search for a new leader commenced immediately. Both internal and external candidates are being surveyed for the position.

"I joined Barclays 16 years ago because I saw an opportunity to build a business out of almost nothing," said Bob Diamond. "Since then, I have had the privilege of working with some of the most talented, client-focused and diligent people that I have ever come across. We built world class businesses together and added our own distinctive chapter to the long and proud history of Barclays. My motivation has always been to do what I believed to be in the best interests of Barclays. No decision over that period was as hard as the one that I make now to stand down as chief executive. The external pressure has reached a level that risks damaging the franchise – I cannot let that happen."