Why can't the UK have both a MP and a judge-led inquiry into the Libor scandal?

Rather than fight for a politician led inquiry over a judge-led inquiry, why doesn't the UK pursue both to investigate the Libor scandal?

The result of pursuing both is that the politician led inquiry which is designed to finish first will be more credible.

Regular readers know the politician led inquiry will find that the only way to credibly prevent manipulation of the Libor interest rate in the future is to base it off of actual trades where all of each bank's trades are disclosed.

Regular readers also know that in discussing the opacity of the current Libor rate setting process, the politician led inquiry will also find opacity in other areas of the financial system.  Examples are banks and structured finance products.

As a result, the politician led inquiry will recommend that transparency be brought into all the currently opaque corners of the financial system - including requiring banks to provide ultra transparency and disclose on an on-going basis their current asset, liability and off-balance sheet exposure details and requiring structured finance securities to provide observable event based reporting.

Politicians know that sunlight is the best disinfectant and that enforcing transparency will clean up the UK banking system and make it the envy of the world.

Achieving this goal makes it logical to include transparency as part of the Vickers' reform package.

Subsequently, the judge-led inquiry can investigate the Libor scandal and the banking system more generally.  Should the politicians miss the need for transparency, the judge-led inquiry can focus attention on the need for transparency in all the opaque corners of the financial system.

Update
From a Guardian editorial,

The details of Barclays' interest rate-rigging will be lost on the majority of Britons, who know not what Libor stands for and have less idea how it tracks back to their own pockets. Asking bankers to rate their own risks may have been like asking tobacco manufacturers to write the health warnings, but the calculation of interbank lending costs will remain a minority sport. The point of principle, however, is stark – and it is more lie than bore. 

Four years ago Lehman toppled, and society learned that complex derivatives that were supposed to spread risk around efficiently instead concentrated it catastrophically. If that was a figurative fraud, something closer to a literal one is now being uncovered. 

Bankers said untrue things about the price they would have to pay to borrow money, with a view to reaffirming the hardy reputation of an institution which was energetically stuffing their pockets. 

This deception was apparently systematic .... plea in mitigation is other banks were at it too. 

That is very likely. Manipulating a statistical average, such as Libor, would be easier in corporate concert than in isolation, and it is understood at least 16 other banks are being investigated. This wider canvas makes the case for the most sweeping of inquiries.... 

Both the main parties fell under the spell of the bankers. 

New Labour invited them into government to advise on things like the NHS, and manage "a public portfolio", which included everything from the canals to the Royal Mail. 

Even after their magic was exposed as alchemy in 2008, they retained great sway which survived the change in administration in 2010. To see that just look at the watering down of several important recommendations of the Vickers commission after lobbying. 

We now know the banks' tricks involved not just dubious wizardry but a measure of wickedness too. That surely gives a final chance to break the spell – it is a chance which must be seized....