Apparently British cops not only have forgotten Peel's Principles,

but they flat suck at their job.

FOLLOWING HIM? Where were their vaunted Armed Police Units? Where were all the "You don't need to protect yourself, WE will protect you" lecturers?

The average police or sheriff's department over here would have found the clown and whacked him, so why couldn't those "We're SO superior to you American lawmen" Brits do it? To borrow from Tam,
"If you are going to disarm your subjects like inmates in the maximum security wing of the loony bin, then you had best step up to the plate when something like this goes down. You refer to self-defense as "vigilantism" or "taking the law into one's own hands"? Well, if you're just going to leave it lying on the ground with the corpses, somebody needs to take it into their hands. "

One of the other sad things about this? If some British subject with a firearms certificate had grabbed his scattergun or rifle and stopped the goblin, you KNOW some dickless wonder in the government would be trying to hang him for 'taking the law into his own hands', etc. ad bullshit.