UK fraud office weighs prosecutions of Barclays

The announcement followed hours after Barclays' chairman, Marcus Agius, resigned and accepted ultimate responsibility for the misbehavior between 2005 and 2009 which cost the company $453 million in fines by U.S. and British agencies.

Britain's Serious Fraud Office said it hopes to decide whether to pursue criminal charges within a month. "The SFO is aware of investigations in other jurisdictions and working with the relevant authorities," it said in a statement.

It wasn't immediately clear whether the SFO was considering charges against the company as well as individuals.

The U.S. Justice Department said last week that individuals at Barclays could face prosecution but the company would not because of its cooperation in revealing how the bank and individual employees submitted false data on interbank borrowing rates.

Agius' departure boosted the bank's share price but also brought fresh demands that Chief Executive Bob Diamond also accept responsibility and resign.

"Everybody is asking when are the other senior people at the top of Barclays going to take responsibility for the things that happened on their watch," Deputy Prime Minister Nick Clegg said.

Ed Miliband, leader of the opposition Labour Party, also called for Diamond to step down. "I want to see criminal sanctions against those who broke the law," he added.

Barclays shares rose 3.4 percent to close at 168.4 pence, holding on to earlier gains despite the SFO announcement.

Diamond, giving no hint that he was considering resignation, sent a memo to bank staff saying that Barclays' own disciplinary process "will be completed swiftly now that regulatory reviews are complete."

Penalties could include clawing back bonuses and dismissal, he said.

"I am disappointed because many of these behaviors happened on my watch. It is my responsibility to make sure that it cannot happen again," Diamond said.

Barclays is one of a number of banks which regularly submit estimates of what it will cost them to borrow from other banks. These estimates feed into calculation of the London interbank offered rate (LIBOR) which is used to determine payments from a range of derivatives contracts.

The London rate, and the related European interbank offered rate, are the benchmarks for over $500 trillion in global contracts, including loans and mortgages.

Barclays admitted that it had submitted lower than actual figures on its interbank borrowing during the credit crisis in 2007 and 2008. Several other global banks are being investigated in other countries for similar actions.

Announcing his departure, Agius said "the buck stops with me and I must acknowledge responsibility by standing aside."