Chatlines to talk to sexy girls and text them
As one of the detectives told me: 'You've got to get their mobile phones examined, their computers examined, their cameras examined and look at every single image.
And yet when officers from the Paedophile Unit raided his home, they found nearly 20,000 indecent images, including video-clips of a 17-month-old baby being assaulted.
But despite often having no criminal record, they pose every bit as serious a threat to our children as the more readily identifiable 'dirty old men' of the past.
'In the past couple of years we've arrested magistrates, lawyers, company directors, police officers, people in the media,' DCI Stevens tells me.
It's very real, it's very nasty indeed and the connection between those internet chats and images of paedophilia are all too common.
I've spent the past 18 months shadowing the officers of Scotland Yard's Paedophile Unit and, despite being a former detective with more than 12 years of experience in child protection, I've been horrified by what I've seen.