Last Thursday, the team’s work in the 18-month Operation Algebra inquiry saw ringleaders of the worst child abuse network uncovered in Scotland jailed for life at the High Court in Edinburgh. James Rennie, 38, and Neil Strachan, 41, both from Edinburgh, groomed children – including in Rennie’s case one of just three months – before exchanging their videos online. Faced with this, it would be easy to understand why a lifetime ban on internet access for convicted paedophiles might seem like a logical step.

Detective Superintendent Allan Jones, (right)  who led the Algebra inquiry, calls for internet service providers to cut off convicted paedophiles, saying more resources are needed to deal with technological advances which have made it possible for anyone with a broadband connection to “plumb the depths of their depravity.”

The case of nursery worker and mother-of-two Vanessa George, who sexually abused infants in her care and then distributed images – mainly via Facebook – with convicted paedophile Colin Blanchard and Angela Allen, is just one high-profile example of how easy it can be to construct a double life online.

Last week, the mother of Ashleigh Hall urged social networking sites to prevent people creating false online identities, after her daughter was allegedly kidnapped and killed by a 32-year-old homeless man she met on the internet posing as a teenage boy.

But the internet has transformed communication as well as crime – from fraudulent email scams to music piracy – in less than a decade, leaving society with a difficult balancing act between civil liberties and protection.

Det Supt Jones said that file-sharing is “probably one of the quickest growth” crime areas thanks to the advent of broadband, enabling faster video streaming and clearer images that can be sent by mobile phone. During his  detective career in the early 1980s, he found it extremely rare for someone to be abused by a “complete stranger” unless  abducted from the street. Abusers would tend to come from within the victim’s family.

“Now...abuse is in a completely different realm,” he says. “People can do it within their homes by anonymously contacting hundreds of children, unknown to anyone in the victim’s environment.”

“There’s probably a greater proportion of people who now, because the images are out there, have an interest in that type of sexualised behaviour. These people are a few short steps away from contact abuse. Presented with the opportunity, the continued exposure to these images heightens their expectations and curiosity.”

He  added that technology used by offenders is unrecognisable since he was involved in Operation Ore, the UK’s first major child pornography inquiry a decade ago.

Det Supt Jones highlighted 2006 as the moment when “everything changed” as broadband’s popularity enabled offenders to store more, larger and better quality images and videos and get access to minors online, requiring “a completely new set of resources we didn’t have” at the time.

His team infiltrated one major group during Operation Abdicate, the first to highlight the lengths to which men would go to arrange sexual encounters with teenage girls through social networking websites. Gary Wilson, 42, from County Durham, Martin Murray, 36, from Irvine, and Daniel Walker, 33, from Glasgow received lengthy jail sentences last year for sexually abusing the same girl, then 13, through Facebook.

Det Supt Jones said: " One of the central players was Daniel Walker, who wasn’t just targeting one girl, but lots, through social networking sites. We went from having one victim to hundreds throughout the UK.”

The internet's dual face
Does banning convicted paedophiles from the internet make sense? Would it work in practice – and, most importantly, would it reduce offending? Almost 99% of all internet service providers run a blocking service which prevents anyone gaining access to known child pornography websites. Software can monitor the online activity of anyone with a known sexual interest in children and produce weekly reports for their counsellor or probation officer.

Already, courts in the UK can impose conditions which can restrict an offender’s access to specific physical premises, to computers and to internet access. Attempts to crack down on internet abuse will also soon see sex offenders routinely registering not just a change of address and credit card details, but any computer login they have – with attempts to use alternative usernames considered an offence in it own right.

John Carr, (left) secretary of the Children’s Charities’ Coalition on Internet Safety, believes that while a blanket ban on internet usage for convicted paedophiles would be “impractical” and “unreasonable”, selective restrictions should apply.  “I don’t think it’s unreasonable to say that someone should be blocked from going to places on the internet where children hang out, social networking sites and so on. It would be technically possible to do that.”

He is also “100% convinced” that the internet has stimulated an increase child sex abuse: “The amount of offending that’s happened of that kind has increased by 7000%-8000% looked at over 10 to 15 years, and it maps directly to the growth of the internet.”

A recurring theme in any attempt to dissect the relationship between internet access and sex offending is whether the web is enabling the abuse, or directly causing it. But ironically, the very vehicle that paedophiles are using is also their main pitfall.

A spokeswoman for the government’s Child Exploitation and Online Protection Centre said: “Whilst it might appear that the internet is facilitating this sort of crime, what it’s also doing is driving a digital forensic trail. Were it not for these individuals sharing emails or operating online, we would never have detected what some of these people were doing offline.”

It is a view echoed by (right) Iain Livingstone, the Assistant Chief Constable of Lothian and Borders Police. The Association of Chief Police Officers Scotland’s lead officer on child protection and Operation Alba, he says forces throughout the UK detect breaches of bail and sex offenders’ register conditions “on an almost daily basis”.

But without the internet, many such breaches might go unnoticed. “The internet facilitates the criminality, but it also facilitates the investigation and identification of child abusers.”

Operation Alba will take a “proactive” approach: rather than relying on lapses in judgment to expose abusers – as in the breakthrough moment when Strachan handed his computer in for repairs without deleting incriminating files – the police are using software to actively track down paedophiles online.

“We’ve lifted the stone and we’re going to have to deal with what we find when we get there,” said Mr Livingstone.