I used to regularly take photos of cops abusing the system. I even once followed a cop going well above the speed limit when their lights weren't flashing. 20km down the road I eventually caught up with them because they'd pulled over... to set up a speed trap! Naturally, my first words were, "'Allo, 'allo, 'allo, do you know what speed you were doing?" (I'm not in UK).
I've caught them blocking traffic to book people getting around traffic jams in the other direction, after watching them speeding and going through a red light, & doing an illegal u-turn.
Double parking. Forcing cars to cross double lines, to book minor infringements. Going almost double the speed limit through a retirement village (90km/hr in 50 zone). Blocking traffic to buy food... my list is pretty long!
Police need to uphold one rule: serve the community by obeying the rules they enforce.
In my country they give themselves almost free reign, to the point where they're almost terrorists.
No amount of social and media propaganda, nor closed door review processes, will rectify the situation, unless atrocious behavior is stopped