Depending from how high it can reliably work from, collaborate with UK CCTV surveillance so that you can better track individuals with fewer cameras as long as you can collate them with cameras that confirm their position at various points in time.

Fly a handful of drones over the area of a fleeing suspect and be able to track their whereabouts and look for suspicious behaviors (eg. someone running and making constant turns in a city or doubling back often, cutting through alleys).

Hell fly a few drones of the city to monitor foot traffic of the population and determine possible points of interest for new developments. Where are people walking to? How do they tend to get there? Can we optimize traffic for them - or more realistically - around them?

Could be used for other forms of crowd analysis too such as how to best disperse a riot and separate a crowd.

Sorry I guess I'm about as pessimistic as you are about it. Use in S&R like throwup238 suggested seems like a good non-militaristic fit for it.

Oh and also this which was posted on HN not too long ago: https://dropofahat.zone/