Now that the CPS have decided that there is insufficient evidence to proceed with any prosecutions in the cash for honours affair, Guido is rounding up volunteers to back a private prosecution. While this is a great idea, there is a risk that the CPS  take over the prosecution and then promptly drop it. The details of their powers in this respect are here; essentially they can drop the case if:

• There is so little evidence that there is no case to answer; or
• The prosecution falls far below the public interest test in the Code for Crown Prosecutors; or
• The prosecution is likely to damage the interests of justice.

It looks to my untrained eye as if the CPS would struggle to make a decent case for dropping it. They have refused to prosecute themselves because they don't think they can get a guilty verdict (let's leave aside the absurdly high standard they have set themselves). This is not the same as having so little evidence that there is no case to answer.

I can't conceive of any argument they could make that the prosecution was against the interests of the public or of justice, so there doesn't appear to be an "out" for the crooks here either.

The other thing to think about is the political fallout of the CPS taking over and then dropping a case against close confidants of the prime minister. It would look nothing if not very, very corrupt. Would Brown really risk it rebounding on him now that Blair is long gone?

So all in all, it looks like it's worth a punt.  We live in hope.