I am a big fan of Derren Brown, through the years he has made me laugh, think, and be struck with awe. This, however, felt a little too staged at times. I get that they have to edit it down to a length and pace that don't scare people away, but it would have benefitted from 10-15 minutes more. I was entertained, though.
What baffles me the most, is the other reviewers here who bash it for its "political agenda". To you I will just say, that when you write stuff like this, it looks like you're okay with people hating, and killing, others for no good reason. Also, you obviously didn't pay attention, as Derren ended the show with talking about how both extremes could come together to find a solution. But maybe you had already turned out, because you were hurt that they told you that killing is bad. Seeing this as a political agenda doesn't reflect well on you. Not killing shouldn't be a left or right issue, it should be a human issue.