He set off to work as Chairman of Barclays - but this was no normal day.

The first item on Marcus Agius's agenda was to submit his resignation.

He fell on his sword over the interest rate rigging scandal which last week cost Barclays almost half a billion dollars in fines.

The bank admitted that some of its traders had attempted to manipulate Libor - the London interbank lending rate.

It's used worldwide to set prices on around 350 trillion dollars of derivatives and financial products.

Agius said it was evidence of "unacceptable standards of behaviour within the bank". He also said it had "dealt a devastating blow to Barclays' reputation."

"The buck stops with me," he added, "and I must acknowledge responsibility by standing aside."

But many are asking whether the buck actually stops with Chief Executive Bob Diamond.

He was in charge of BarCap - Barclays investment bank - at the time.

He plans to fight on but faces a grilling from British MPs on Wednesday over the scandal.

The hearing could prove embarrassing to the Bank of England

There are reports Diamond and a BoE deputy had a conversation in 2008 about Libor.

It apparently led some people at Barclays to believe mistakenly the Bank of England had granted permission to submit artificially low Libor estimates.

More than a dozen other banks are being investigated in the long-running investigation by authorities in North America, Europe and Japan.

Citigroup, HSBC, UBS and RBS are among them and more big fines are expected.

Sonia Legg, Reuters.