We have to understand how the extremists got the way they are. Without that kind of understanding, we'd never really get to know them. I put in nothing about their childhoods. But what I have put in is stuff about the weird symbiotic relationship between us and them.

When I was 20, I wrote a film on spec and sent it to the BBC. They wrote back, 'Usually, when we reject submissions, we like to offer some encouragement, but in your case, we don't see any point in you continuing.' I took it as encouragement anyway, thinking that only people who write terrible things are capable of writing great things.

My paranoia never ends, but I haven't been paranoid about being spied on my shadowy forces for some time now.

But on the extremist side I didn't get any rejections at all. Everyone agreed to talk to me.

At first, I did stories on people who were maybe just eccentric. Omar was a natural progression from that.