The Hotline is split into two workstreams as illustrated below; reports assessments and imagery assessments. On this page, our focus and analysis is on the outcomes of the imagery assessment workflow.
We use our bespoke grading and hashing software, called IntelliGrade, to enable us to perform an image-level assessment of images and videos. This also creates a hash of the image or video. A hash is a type of digital fingerprint created using a mathematical algorithm that identifies a picture of confirmed child sexual abuse.
Each hash is completely unique. Once an image has been hashed, it enables us to share these with industry and law enforcement, eliminating the need to view the criminal imagery.
Hashes are quickly recognised; this means thousands of criminal pictures can be blocked from ever being uploaded to the internet in the first place.
The IWF began hashing child sexual abuse images in 2015.
In 2021 we launched our Taskforce, a team dedicated to assessing images and videos, which was originally funded by Thorn and then by the Home Office as part of partnership with the UK Government’s Child Abuse Image Database. (CAID)
By the end of 2024, we had accumulated 2,883,015 individual hashes of criminal imagery which includes 122,487 videos.
As well as providing an analysis based on ‘reports’ of child sexual abuse, where a report of a single URL may contain one, or many tens, hundreds or even thousands of different images, we also record additional information on individual criminal images. For singular imagery we are able to record more detailed information, called metadata, such as the age and sex of each child, and the type of sexual activity seen.
When our assessors review an image, they identify and record the most severe category of sexual activity and the age and sex of the youngest child subject to this activity. They will then record the age and sex of any additional children seen in the same image. Each image or video will therefore only have one category assessment regardless of any additional sexual activity seen.
For example, in an image showing Category A abuse of an 11-to-13-year-old and where a 0-to-2-year-old is also seen, Category A would be recorded for the image. The 0-to-2-year-old would be recorded as an additional child, but no additional category would be applied.
There is additional complexity when assessing videos and collages comprised of multiple images - including those that may show several children – which means that we only record severity in these cases. This contributes to greater efficiency and helps to protect the wellbeing of our image assessors without compromising the accuracy of our work.
