My OH has a friend from way back - they both worked together frequently for many years as mechanical engineers and stayed in touch. He is an apostate from Islam and, having renounced his religion, he had to, basically, cut himself off from his family (not married, so there was no wife to consider)
Although he no longer lives in fear of any reprisals from the family, he still lives far away from his original patch. He talked about it, a bit. It's just not that easy for a Muslim to renounce his/her religion if there are family, friends or acquaintances. Depending I suppose on their degree of devotion to their religion, they may well harass and intimidate the apostate. Our friend was accused of (among other things, I guess) being indoctrinated with evil Western culture. I can't quite remember how he put it, but that was the gist of it. I can't imagine he came to this decision lightly, overnight so to speak - because he knew it would drastically alter his way of life.
If the perpetrator of this horrific attack in Clapham has indeed converted to Christianity, and has family, friends or acquaintances here in the UK who are protecting him, they must be very forgiving of his apostacy and conversion.
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I am cynical.