The UK’s Internet Watch Foundation (IWF) is to work with a US counterpart to create the biggest database of hashed child abuse images in the world to help fight the spread of such content.

The IWF will work with the National Centre for Missing and Exploited Children (NCMEC) in the US to share known content with each other – helping internet companies stop the upload, sharing and storing of such content.

Hashing is a form of digital fingerprint which allows an image to be identified the moment someone attempts to upload it.

The IWF identifies and removes online images and videos of child abuse, as well as offering a place for the people to report them anonymously.

The agreement will see a new database created in the NCMEC’s CyberTipline hub, which is also used to report instances of the online sexual exploitation of children.

Combined, more than 3.5 million hashes will be in the expanded database – which will be used by online firms to help stop images and videos of abuse being uploaded to their platforms.

IWF chief executive Susie Hargreaves said the new system and larger database would help internet companies better police their sites and provide greater protection for victims.

“This will be the biggest quality-assured database of child sexual abuse hashes in the world,” she said.

“The IWF-NCMEC collaboration has been inspired by our joint determination to make it as easy as possible to remove child sexual abuse images for the benefit of the victims pictured.

“Child sexual abuse material is a global issue which knows no geographical boundaries.

“This hash sharing agreement joins up efforts to ensure that the best service is given to victims of sexual abuse, and the best efforts are made by NGOs and internet companies to rid the internet of duplicates of child sexual abuse images.”

The UK charity uses the Microsoft-developed PhotoDNA hashing software as part of its work.

John Clark, president of the NCMEC, said: “The expanded partnership and addition of IWF’s hashes to the NCMEC platform is groundbreaking.

“Two of the largest organisations working to combat the online sexual abuse of children are joining forces to make sure survivors of this horrific abuse have some peace of mind that there are increasing safeguards in place to reduce the amount of content being circulated online.

“This agreement is a game-changer and we look forward to other organisations joining the effort to share hashes to combat this global epidemic.”