A charity which protects young people in Burton and South Derbyshire says potential damage caused by cyber-bullies is "impossible to fathom" - including sexual abuse and hate speech.
The NSPCC has hit out after a new report, conducted by charities The Children's Society and YoungMinds, claimed that technology giants were placing youngsters' mental health at risk due to online harassment.
Cyber-bullying, including the sharing of embarrassing photos and threatening, intimidating or nasty messages, is said to be on the rise while the study revealed children and young people were using social media for hours every day, often across multiple profiles.
A survey of 1,089 respondents aged 11 to 25 found almost one in 10 admitted logging on after midnight every night while the report found that 61 per cent had a first social media account at the age of 12 or under.
More than a third of those polled said social media had a negative impact on how they felt about themselves, while just 23 per cent said it had a positive effect.
Ally Sultana, NSPCC campaigns manager for Derbyshire and Staffordshire, said: "It is simply wrong that the Government has allowed social networks to mark their own homework for the past decade, and that their new strategy would let that continue. It means that new services would continue to be aimed at young people without legally enforceable obligations to keep those children safe. We don’t tolerate that state of affairs for children offline so we shouldn’t tolerate it online.
"It is impossible to fathom how much harm has been done over those years in terms of online sexual abuse, hate speech, violent and harmful content and cyber bullying.
"Government must seize the opportunity to right this wrong in its Internet Safety Strategy and bring in a mandatory rulebook for social networks to protect children now and in the future."
Describing their views on social media usage in an evidence session, one youngster said "it's almost like a drug," while another said: "Nobody really goes out anymore."
A 15-year-old-girl said: "You kind of expect to experience it: nasty comments on the selfie, Facebook posts and Twitter posts, people screen-grabbing your Snapchat story to laugh about it ... I feel like it's something people don't take seriously."
Matthew Reed, chief executive of The Children's Society, said there were positives and negatives to social media use.
He said: "The inquiry has heard from young people describing cyber-bullying as 'inescapable' and in the most extreme cases it has pushed some to the verge of suicide.
"But we have also heard about the positives that social media brings for young people."
YoungMinds chief executive Sarah Brennan said the inquiry "has shown loud and clear that it's time social media companies sit up and take action to tackle cyber-bullying."
Snapchat told the inquiry any content found to violate its guidelines is removed and could lead to the termination of an account. The company's owner Snap said it does not tolerate harassment and bullying and provides effective ways for users to block and report offenders in the app.
Twitter's rules state: "In order to ensure that people feel safe expressing diverse opinions and beliefs, we prohibit behaviour that crosses the line into abuse, including behaviour that harasses, intimidates, or uses fear to silence another user's voice."
In evidence to the inquiry, Facebook said it had a "particular focus" on anti-bullying measures and takes extra precautions for teenagers.
The company said: "For example, our anti-bullying policy makes clear we remove content that appears to purposefully target private individuals with the intention of degrading or shaming them."
In written evidence, Google and YouTube said: "We understand the duty we have to ensure our platforms are used responsibly, that users have the tools and knowledge they need to make responsible choices online, and that they are able to flag and report abuse so that it is acted upon."
