You have to bear in mind, in the UK the average police officer doesn't carry a gun, be it taser or otherwise.
See above point. It will very rarely happen here.
You have to remember that law enforcement is very different in the UK.
Sam's hit the nail on the head.
To give you an idea, since those outside of the UK aren't "getting it"; if a normal citizen had done it, they would've been fined, given penalty points, strung up and tarred in the gallows as Eric Arthur Blair rolls over in his grave, whilst the rest of the populous sit back as the government condemns that man to live forever in the panopticon that Britain is becoming (getting a driving licenses elsewhere in the world can be somewhat interesting, if you have convictions and lets be honest, living without driving in todays world is somewhat... tricky?).
Yes there are far worse places to live, but consider Britain's history. Further examine our country's hypocrisy in the past and you might understand why a certain subset, which branches out further than the uneducated Daily Mail reading masses, are somewhat pissed off and would like it all to end.
Sing it again Brother.
As cynical as I maybe, I can only see them using it as an excuse to put more surveillance in.