Roblox presents itself to parents as a safe space for kids. Behind the scenes, it's waging a technological shadow war against condo games: digital sex parties where kids are flirting with danger.

Roblox is a huge sprawling world of games which is sometimes described as a kind of primitive metaverse. It's one of the most popular children's games in the world.

Roblox is the most popular game for children under 13 right now. But some charities and safety experts say that more children are finding upsetting and abusive content on the site. Newsround's ...