Speaking as a ground bound copper (and PPL(H)).
I don't give a cr*p how much they cost. They are worth their weight in gold.
People just see the Cops on TV programmes then put 2 and 2 together to get 5.
The ASU aircraft protect me as well as the public. If I'm behind a vehicle that is failing to stop I, as well as the public are at risk from the un-trained driver behind the wheel of the fleeing vehicle. Get an EC-145 overhead and I can back off (protecting me) which in turn will hopefully encourage the other vehicle to slow down (protecting the public). The observers can then coordinate other police units including 'stinger' equipped units to bring the incident to a safe conclusion.
The aircraft are used to track individuals on foot, search areas for missing or vulnerable persons, scan rivers and lakes using thermal imaging equipment.
They have been used to assist firebrigades to identify hot spots and consequently to more effectively tackle fires.
I have used them to plan drugs raids, to search for casualties thrown out of vehicles involved in serious road traffic accidents.
The ASU saved my life once while chasing a suspect involved in GBH on a pregnant girl. He ran down an embankment and I chased him along some railway tracks. The observer was able to warn me of an approaching train.
They are also used in many operations that cannot be discussed in open forum.
In short, let the naysayers whinge and moan and throw ridiculous figures around. They know little of the realities. Their lives are made safer in more ways than they know by those aircraft.
LM