More than a dozen current and former employees of several large banks under investigation have hired defense lawyers over the past year, but Levander's role is one of the most high-profile.

Levander, a partner at the law firm Dechert LLP, is one of the biggest names in the defense bar in the United States. He is currently also representing former New Jersey governor Jon Corzine in investigations into the collapse of the failed commodities brokerage he ran, MF Global.

Levander, who is known for his trademark bow ties, had a prime seat by Corzine when the former CEO was grilled multiple times at congressional hearings in Washington late last year.

He has also represented outside directors of Lehman Brothers Holdings Inc, former Merrill Lynch CEO John Thain and hedge-fund manager and philanthropist Ezra Merkin, who was sued over money lost in the Ponzi scheme run by Bernard Madoff.

A person representing Diamond declined to comment. A spokesman for Barclays Plc (BARC.L) declined to comment. A spokeswoman for Dechert declined to comment.

It is unclear when Diamond hired Levander and Dechert.

Barclays (BARC.L) last month agreed to pay $453 million to settle charges that it manipulated Libor -- the London interbank offered rate, which is compiled from estimates by large international banks of how much they believe they have to pay to borrow from each other.

No individuals have yet been charged in the sprawling Libor probe, which involves several global banks and enforcement authorities.

Diamond resigned as Barclays chief executive less than a week after the settlement, which unleashed a furor in the UK.

British lawmakers on Tuesday accused him of misleading a parliamentary inquiry into the Libor scandal, an allegation that Diamond denied.

Diamond had been CEO since the start of 2011, and been at Barclays for 16 years.

Libor is used for $550 trillion of interest rate derivatives contracts, as well as influencing rates on mortgages, student loans and credit cards.

(Reporting By Aruna Viswanatha in Washington and Steve Slater in London; Editing by Karey Wutkowski and Tim Dobbyn)

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