03/07/2012 12:23 BST | Updated 03/07/2012 12:25 BST

Bob Diamond's Resignation - The Questions He Still Has To Answer

Bob Diamond will appear in Westminster at 2pm on Wednesday to answer questions from the Treasury committee on the Libor interest rate fixing scandal.

Despite resigning on Tuesday, Diamond will still have to face this grilling, which will inform the subsequent planned parliamentary investigation into how widespread the rigging was among bankers in the City of London.

Among the questions Diamond is likely to face:

What was the motive for those who rigged the Libor rate, for how long did it take place?

Barclays says only a few individuals knew of the Libor-rigging conspiracy, and none of these were senior managers. Those who've resigned say they've done so because the buck stops with them. MPs will be looking for any sign from Diamond that people at the top knew.

What was the expected advantage it gave to the business and what impact did it have on customers and consumers?

MPs will be hoping to get a figure out of Diamond, the amount Barclays Capital gained from the rigging of Libor. They will expect Diamond to explain the wider impact of the scandal. They'll probably also want to try to get a sense of how much Diamond himself personally profited, amid calls for him to hand back previous bonuses he earned.

When did you become aware that Barclays Capital staff had been rigging Libor?

The MPs will want to know what safeguards Barclays had to avoid improper practices, why these failed and when Diamond had become aware they had failed. Who was interviewed internally, by whom and what was the outcome of those discussions?

How many other institutions are likely to be involved with this?

This is the question people probably want answered most urgently but could be difficult for Diamond to answer, because there are a number of seperate investigations by the FSA underway already.

But MPs will be interested to get a sense of whether it was an industry-wide conspiracy. Critically conversations between Diamond and senior officials at the Bank of England will be probed - there is a suggestion Barclays staff felt they had the implicit blessing of the bank in what they were doing.

What will your severance package be from Barclays and do you intend on taking all the money?

Diamond's severance deal from Barclays could be as much as £17m. As with Sir Fred Goodwin Diamond might find it difficult in the years ahead if he takes that much, since he clearly presided over something highly suspicious at the height of the credit crunch.