Last year saw a 136 per cent increase in identified and subsequently removed child abuse imagery, according to a just-released report from the Internet Watch Foundation (IWF).
In its Annual Report for 2014, the body revealed that its new ability to actively seek out criminal content has been effective in allowing it to identify more material than ever before.
The IWF, an industry-funded charity and watchdog, has been the UK's hotline for reporting child sexual abuse imagery online since 1996, and actively attempts to minimise the availability of child abuse images.
Historically, it functioned by receiving reports of suspected child abuse images from the public and investigating the material itself, issuing a notice of takedown to the hosting company if IWF staff assessed the material as illegal.
It also maintained a confidential blacklist for ISPs to sign up to.
While the blacklist and hotline services are still available, and remain a important part of the IWF's work, the charity now pro-actively searches the web for child sexual abuse images, its mission having escalated after a June 2013 summit organised by then Culture Secretary Maria Miller.
In the aftermath of the murders of children Tia Sharp and April Jones, a memorandum of understanding between the Crown Prosecution Service (CPS) and the Association of Chief Police Officers (ACPO) concerning section 46 of the Sexual Offences Act 2003 was revised to include the proactive role of the IWF seeking out such material.
"[Our] analysts pass a long and detailed recruitment process, receive high-level training and psychological support through monthly individual counselling sessions and quarterly group sessions," an IWF spokesperson told The Register.
The IWF said it helped remove 31,266 URLs containing child sexual abuse material during 2014, compared with 13,182 in 2013, by actively searching for images and videos using intelligence-based tactics.
The IWF counts removals by URLs, which it explains may contain just one, or many, many, images and videos.
The report noted: "Less than 0.3 per cent (95 URLs) of the imagery identified last year was hosted in the UK (while in 1996, 18 per cent was UK-hosted) and 95 per cent was removed within a day, often within two hours. Last year, most material was hosted in North America (56 per cent) and Europe, including Russia (41 per cent)."
The IWF explains that its takedown notices were more successful too as victims' images were also being removed at a much faster pace, meaning images which had been identified globally had a shorter life-span online.
An increasing amount of the identified child sexual abuse images were located in image hosting services and cyberlockers, where access may be shared among abusers without exposing the images to watchful authorities.
The IWF has come under criticism for operating a blacklist which smaller ISPs have felt pressured to subscribe to, and which is of questionable use in preventing access to child sexual abuse material.
The IWF spokesperson told The Register: "The most effective way to disrupt the availability of child sexual abuse material is removal at source. We consider the filtering of known child sexual abuse imagery based on our URL list as an important, yet temporary, measure while awaiting removal at source." ®