ThinkUKnow - Thinkuknow is the education programme from CEOP, a UK organisation which protects children both online and offline.
Safety Net Kids - Great website with tips and resources for child safety and wellbeing.
Childnet - Children's activity zone with games and advice
GoBubble - Safe social media for kids
Common Sense Media - Provides independent reviews, age ratings, & other information about all types of media.
Children's Commisioner - Simplfied social media terms and conditions for young people