And that wannabe, murdering little shit epitomises a leading misconception about the benefits some associated with Brexit: the UK problem didn't begin with Europe - it began with the end of Empire and the ready influx of people from Asia, Africa and the Caribbean, all counties with no relevant connection with our membership of Europe whatsoever.
From there we got the spreading drug culture, the different sense of the value of human life, and the different levels of violence that were likely to be committed compared with the types of violence our own white criminals were likely to offer us. I have it from my late police chief inspector neighbour that the olde "fair cop, guv" relationship was not fantasy at all, but that a code of understanding between criminals and police did exist. No more. They are now just as likely to get killed by gangsters as are other gangsters. It was the former situation that largely led to the lack of enthusiasm for police members carrying guns: they had better ways and protocols than that, but sadly, these no longer apply.
But, the 50s problems of migration have been confused with people from Europe who yeah, are not always saints either, but then we have our own crazies born and bred on the island, so we shall be no safer. That misconception is why you keep hearing the bleat about "control our own borders" without the realisation that it's too late, you can't, today, correct the errors of over seventy years ago.
And even if you could use your time machine, how would you use it? By no means were all of the immigrants bad people; many came with deeply held Christian religious beliefs, with skill sets and often with a great deal of money, and where that money was unable to be imported because it was stolen by the countries they fled, they did manage to smuggle in their entrepreneurial skills and start again from scratch; hell, they even managed to displace fish and chips as the national favourite!
As with all types of things in life, all people are not equal and the doctrinarial refusal to accept the obvious is why we have so many idiots in jobs, and so many people getting into the country that should never be allowed into it. Before Spain was into the EEC, you had to be able to show that you could support yourself from external funds before you were allowed to settle. That was the way to go, and would have solved many social problems had it been applied more strictly in the UK.
Ah, hindsight!