Political Week Ahead - Bob Diamond And David Cameron Grilled By MPs

The box-office event at Westminster takes place on Wednesday, when Barclays boss Bob Diamond appears before MPs on the Treasury Committee to answer a string of awkward questions about the Libor scandal which has gripped his bank.

It's likely to be the moment which determines whether Diamond can hang on in the job - many suspect he'll be gone by the end of the week. But the evidence he gives could have massive implications for the whole sector, if Diamond reveals which, if any, other UK banks were involved in the rigging of Libor.

Treasury Committee chairman Andrew Tyrie has become more noisy lately, far more prepared to flex his political muscles and demand answers. Tyrie's not the sort of MP you'd want to be the wrong side on; if Diamond doesn't have good answers to the MPs' questions it's likely Tyrie will get irritated.

Earlier in the week we'll see David Cameron's regular appearance before the liaison committee - where a dozen senior MPs ask him a variety of questions. The topics under consideration this week are the impact on the UK of the eurozone crisis and civil service reform.

Cameron will have to explain in more detail why he's made the half-promise of an EU referendum, and in particular why he timed it for this weekend? Was it to head-off the expected speech by Liam Fox on Monday morning? HuffPost suspects to.

In the Commons the Budget (or what's left of it) goes through its remaining stages of consideration before becoming law. Labour is pushing for more U-turns on the Granny Tax and for a cut in VAT. They're unlikely to get their way but Osborne is also facing an amendment from his own side.

Lib Dem MP Stephen Williams is trying to stop the chancellor from relaxing tax-avoidance rules for big UK-based multinationals. It's only a minor amendment but given the parlous state of coalition relations, could the Lib Dems rally round their colleague and cause another embarrassment? We wouldn't put it past them.

Stephen Williams is also among MPs calling for a Leveson-style inquiry into the Libor scandal at Barclays. Labour's position on this seems to change every hour - one minute Ed Miliband is calling for a full-blown, judge led inquiry, but some of his junior shadow ministers have been less keen and former chancellor Alastair Darling doesn't think one is required.

One prediction though - as the week plays out the calls for something like Leveson for the banking industry might become irresistible. When journalists have been hauled through the mill they're likely to be the loudest voices calling on bankers to get the same treatment.