Bleg: What is the issue with money for P&J?

Exciting innovation! The excellent Freakonomics blog occasionally runs a “bleg” defined as:

    A bleg = blog + beg — i.e., using a blog to beg for information.

In that spirit, the following types of comment keeps popping up regarding the devolution of Policing and Justice:

    PSNI is in serious financial trouble at present, if a serious terrorist campaign were to raise its’ head, where would additional funding come from?

    No Government will promise a blank cheque, that is for sure. Posted by New Blue on Sep 13, 2009 @ 10:02 PM

And generally it seems accepted that there is a big issue with money. But to reveal myself as an idiot, um, why?

The PSNI must already have a budget, otherwise police officers wouldn’t get their salaries, stations wouldn’t have their electricity bills and rates and whatever else wouldn’t be paid, training wouldn’t happen. It just must be adminstred somewhere else. Does the money not follow to whoever is in control? And if, for example, a major new campaign kicked off, the central government almost certainly would spend any money neccessary to fight it – exactly a blank check. Why would it play games over jurisdiction and give no further help if powers were devolved? Surely that would be a scandal? I don’t understand this objection but lots of important and serious people keep talking aqbout it, so is anyone able to explain what the problem is, exactly?

EDIT1:

Okay so far we have the following explanations

1. Follow my links, and the links after, and watch the videos on the links (Pete)
2. The executive is too incompetent to handle the budget cf ILA et al (New Blue)
3. Fighting a future campaign would require more funds, and central government won’t give them but will if they are in control (Fair deal)

I’m not entirely satisfied with any of them, see comments. Any better ones?