As a former police driver (in a non-standard capacity and non-standard environment - details withheld to protect the guilty
) I was assured that, in the force for which I was working, I had powers of arrest whilst on operational duty.
I can also confirm the exemption from both the 500' and the 1500' rules. I recall one operation we carried out which gave cause to us (me and the boys in the back) wondering how a conversation in court might go:-
"Captain Stable, would you like to inform the court exactly
why you were flying over the city at 200 feet above ground level?"
"Certainly - because I
can 
"
We also had the option of invoking the Official Secrets Act, the Defence of the Realm Act and a host of other stuff. CAA FOI's didn't like visiting us and inspecting the Discretion Reports because they all said "Due Operational Reasons" and nobody told them any more than that. I hate to see a grown CAA man cry...
