Last week I was interviewing more teenagers, as my book Generation Z: Their Voices, Their Lives is finding its way to the television screen.
Two boys, neither of them yet fourteen, gave an interview so filled with pathos and bleak humour that the crew and I spent the hour veering between great mirth and sadness. They described a life with one foot still in childhood (PlayStation, getting told off, riding bikes) and the other in a fairly brutal adulthood (police, guns and riots.) Both come from backgrounds and parts of London where poverty, violence and gang culture are rife. Fortunately, both were in an excellent programme called Gangs Unite (http://gangsunitecic.org.uk) which aims to intervene in the lives of young people who are vulnerable to gangs and crime.
One of the most striking things they talked about in a totally matter of fact way was the proliferation of the sex trade. In their immediate environment were prostitutes, pimps, and brothels. So far, so normal, you might say - London has always had a sex trade. But it gets worse.
Where once young men wanting to make a fast buck took to the drug trade, they now have the very profitable (and less risky for them) skin trade. Younger men (and boys) have always been useful to older men involved in crime - mostly to run drugs. But the older men have wised up to a bleak fact very quickly. Teenage boys know teenage girls. They are mates with them, go to school with them, date them, or share a family with them. And teenage girls are a very, very marketable commodity in the sex trade.
So you can sit there on a bright October morning and talk to two angelic looking thirteen year olds. Both of whom have thus far resisted the lure of this kind of crime, but both of whom know many people involved. Someone's sister being pimped out, an older brother's old school friend on the game, a boy a couple of years older who has set himself up (or been set up) as an intermediary pimp.
The factors that drive the sex trade are complex - poverty, misery, ignorance - as well as the much simpler (but no less unpleasant) supply and demand.
We live in a country where there is real, serious, grinding poverty - and where that exists, prostitution and pimping will sprout like a grim fungus. And young people - children and teenagers - are getting tangled up in this.
What is also apparent talking to the young women involved in this, is how craftily it is being marketed to them. Sure, violence, blackmail and coercion are used regularly. But they are also being told that it is normal, glamorous and fun to earn a buck on your back, or on camera or taking your clothes off.
And this argument can work powerfully. This is a world now so soaked in sex, porn, and people getting famous and rich off making sex tapes or stripping or shaking their enhanced butt in a rap video - that there exists a weird logic to this line of thinking.
Teenage girls I spoke to, who were involved in the sex industry (or considering it) all had things - riches, designer labels, fame, flash cars - dangled in front of them. And they associate these things with people, they seem to want to emulate.
As Lana, 16, told me: "Kim Kardashian made a sex tape, Amber Rose is a stripper, and Nicki Minaj started out as a dancer in rap videos. And look how their lives have turned out."
The recent documentary Hot Girls Wanted looks at the amateur porn industry in the USA. It showed how thousands of teenage girls flock to porn sets every month convinced this is their ticket to easy fame and money. They invariably leave a couple of months later, lives, souls and often bodies in tatters.
We don't have a porn industry like the USA yet, but we do have a booming sex industry, which seems increasingly normalised to young people. With sexy prostitutes in "Hollyoaks", the jolly and glamorous japes of Billie Piper's high-class call girl in 'Secret Diary of a Call Girl' and endless documentaries like 'High Class Call Girls', "My Designer Vagina' and 'A Very British Brothel' - sex is a serious commodity and lot of kids, male and female, want in.
But the sex industry is not what we see played out for our entertainment on the screen.
It is thirteen-year old boys telling you on a bright October morning about a girl they know. A girl who might not yet be sixteen (they weren't sure), who is being forced to prostitute herself by a boy not much older than her from a garden shed in a long-abandoned allotment in East London.
And it is Dina, now nineteen, who was forced into prostitution aged fifteen by her then boyfriend.
"Because of what happened to me, I'm suffering from PTSD and now being treated. Young girls are taught to be wary of older men, but not boys their own age. And that's how they get to you - with someone you might have grown up with."
Chloe Combi is the author of Generation Z, published in paperback by Windmill, £8.99