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Twenty years ago, a predatory paedophile would have had to loiter around parks, funfairs and swimming pools to gain access to children, where his suspicious behaviour - in full public view - would often have raised the alarm before he could cause any real harm.
But computers and the internet have brought an end to all that.
Chillingly, it seems paedophiles and offenders really do now come from all walks of life.
Take Andrew Lintern, for instance, one of the men I saw being arrested, who had travelled to London from Hertfordshire in the hope of having sex with a 13-year-old girl.
What you have to remember is that for each and every one of those images, a child has been coerced, assaulted and badly hurt.
Many will have been raped and, in a few tragic cases, the victim may even have been killed. Despite the horrific nature of these crimes, the problem seems to get worse every year.
No, the sickening truth is that he's pretending to be a 13-year-old girl and he's in one of those internet chatrooms so beloved of our teenagers. The man, of course, is a paedophile; one of the most feared and loathed figures in today's society. well, she could be my daughter, your daughter or anyone's daughter.
Using modern text-speak to pass muster as a teenager, he taps out an innocent-sounding question, the sort one teenage girl might ask another. ' 'No,' replies the very real 12-year-old, giggling as she types. But the girl, sitting at her computer in the comfort and supposed safety of her own bedroom. As a father, I know it's important not to oversex-state the danger our girls are in but, as a former policeman and professional child protection consultant, I also know the paedophile threat is out there.
To catch the new breed of paedophile, you see, has required a new form of policing and Scotland Yard's Paedophile Unit has led the world with its pro-active approach.
What my time at the Paedophile Unit has revealed is that the days when a lazy stereotype of a paedophile - a male, middle-aged loner, often still living with his parents - are long over.
Yes, child protection officers do still come across the sad and dangerous individuals who could be described in that way, but increasingly they are arresting a new breed of paedophile.
Lintern later confessed that the man assaulting the baby in the videoclips was, in fact, himself - an admission that no doubt contributed to him being ordered to be detained indefinitely when he came before Southwark Crown Court earlier this year.
What's brought about this seachange in both the number of paedophile and the backgrounds they come from, of course, is the internet.
Often married and with children themselves, they can be well-educated and highly successful in their field.