Mersyside would be a good place to collect data on the possible effects of NPAS.
They have lost an aircraft from Liverpool, and the others carry out cross border ops as a matter of course. It's almost a mini NPAS and it's pretty much running now.
How has the crime rate changed?
How effective has it been getting an aircraft on scene in time?
Do the boys on the ground even bother calling for air support?
Do they feel more or less confident in their air support?
Surely these questions can be answered fairly easily, if anyone cared to ask them, officially.