Bob Diamond, chief executive of Barclays, was engulfed in a political firestorm following revelations of his bank’s attempts to rig market interest rates for financial gain, sending shares in Britain’s biggest bank down almost 16 per cent.

The fierce political reaction followed Barclays’ decision to pay fines of $450m to settle investigations by regulators in the US and UK into attempted manipulation by banks around the world of the London interbank offered rate, used to set the price of everything from home loans to credit card fees.

“People have to take responsibility for their actions and show how they’re going to be accountable for those actions,” David Cameron, prime minister, said after his chancellor, George Osborne, had questioned in parliament what the Barclays boss knew and when. “It’s very important that goes all the way to the top of the organisation.”