Groups promoting harmful content on social media have featured in high-profile cases, including the death of Molly Russell in 2017.
An inquest concluded the 14-year-old ended her life while suffering from depression, with the “negative effects of online content” a contributing factor.
Her father, Ian Russell, said it was “really disturbing” there was a WhatsApp group targeting such young children.
He added the platform’s end-to-end encryption made the situation more difficult.
“The social media platforms themselves don’t know the kinds of messages they’re conveying and that makes it different from most social media harm,” he said.
“If the platforms don’t know and the rest of the world don’t know, how are we going to make it safe?”
