A search along the lines of "arrested assault robber" shows many cases reported in the Daily Mail, Sun, Mirror etc where the opposite happened, but only a single case where the bystander was arrested -- in that case, because the robber died [1].
Anti-social behaviour and minor criminality is the result of decades of underinvestement in education, regions outside London, austerity and an unbalanced economy [2].
[1] http://www.telegraph.co.uk/news/2017/07/16/have-a-go-hero-ar...
Ill informed leftist ideology trumps unsubstantiated right-wing meme thanks to a random Guardian link.
The muscular memory kicked in and I responded to the attack ferociously. I hit him once, twice, three times (blood was splashing around), then finished him with a kick which sent a few of his teeth out. The guy was laying on the floor and yelling as if he was being skinned.
I called the police, they came and I explained them that I was attacked and that this was the effect of my defense. They dutifully noted that I was afraid, shocked, terrified, etc. and beside a round to the police station to sign off a paper I never heard about the ceases again.
I believe that that the response should be proportionate, but to the clear advantage of the victim.
Being hit once and hitting 5 times back - OK. Being slapped and responding by a kick to the body and then another one to the head - OK. Someone attacks you with a knife and you shoot him back with a gun - OK. Being attacked by a 15 yo and hitting him back as if he was an adult - OK
All these is defense against unknown and there is no reason to stop before you are safe (you do not know what that person is going to do next).
Hitting someone, he is not lying on the floor unconscious and you keep on kicking his head - not OK, there was no more risk. Someone runs away with your bag and you shoot him in the head - not OK, you were not in direct danger.
What I want to say is that the proportionality should have a 10x factor in favour of the victim.
Hitting someone, he is lying (without the not)
It's not a harmless prank if the normal reaction is to hold the prankster down. Plus, you are relaxing, taking some downtime and some know-it-all-i-am-funny-oh-you-are-not-you-are-the-downer comes and stages an agression for fun. « It's a prank, bro. »