Policing in the UK has always been very hands on, largely due to the fact they are, as a rule, unarmed. In countries such as the US, and most of Europe, the officer possessing a fireamr has to confront persons from a distance, when they get up close and personal it tends to go wrong. A high proprtion of Police officers shot in the US are done so by their own firearm.
jamsey is correct - every time an incident like this is put under close scrutiny, the police become a little more apprehensive about using force on subjects, no matter what the situation. This trial (if there is one) will set a massive precedence for deaths after police contact, and if the PC is convicted, you can bet your arse a lot of the public order trained officers will jack that side of their job in. Why would you want to put yourself at risk policing protests knowing if, during the unpredictable mayhem, somebody dies or is seriously injured, you face jail for manslaughter/GBH?
The newest generation of police officers tend to be risk averse as it is. If handled badly this will only compound the situation, and you'll be left with an increasingly violent island nation being policed by officers scared to restrain subjects for fear of prosecution and/or having your life torn to bits in the media.
Police morale is already at an all time low. Big cuts have been made, with further pay reductions and freezes on pay rises for the next couple of years. With everything being put under a microscope, loss of the 'early retirement' after 30 years service, and all the other bollocks lined up for the police, who the hell would want to do this job anymore?
Anyway, I digress. All this public dissection of the police, coupled with the Winsor report, should make for an interesting year. It's going to be a fun summer when the ne'er do wells start rioting, and nobody is willing to take them on, or is forced to do so. I'm sure somebody said "I'd rather have ten volunteers than a hundred pressed men." When the shit hits the fan, I'll be taking care of my own, thanks very much.
And the vast majority of police will help you when needed, and do a bloody good job too. There are a few rotten eggs, but aren't there always?
The drive to get police onto the 'frontline' and into the public view has hit back office functions hard, and don't forget the loss of hundreds (if not thousands) of civvie staff is putting further strain on the 'frontline'. Do you really think they emplyed all those civilian staff to sit on their arses and do nothing? Many performed vital support roles which have now been lost. Who's going to suffer? The officers and the public, who else.
When you have ten patrol officers covering a town of 200,000 people, they aren't going to be able to see you all.